THIRD    E1DITION 

OF   THE 

MANUAL 

era  Surveying  Instruments 


AND    THEIR    USES, 

CONTAINING  USEFI  L   [NFORMATION  FOR  THE 

CIVIL   KNCINKKK   AND   STKYKYOR. 

TO<;ETHKK  \vrni  A 

CATALOGUE  AND  PRICE    LIST 

. 

SCIENTIFIC    INSTRUMENTS, 
PARTICULARLY  THOSK  OK  TIN-:  CIVIL  T>  RVKYOR. 


MAJJK    HV 


F 


THE  A  LIETZ  COMPANY, 


2,^    SACKAMKN1X) 


SAN  I;F  \N(  isro,  (.\\LII--ORNIA. 

1899. 

PRICE,    50  CENTS. 

1VBUSHKD    RY    THE    COMl-ANV  . 

J.NKIUNOEMEXTS     \VILI.     BE    PROSECUTED. 

ESTABLISHED    1882. 


UNIVERSITY  OF  CALIFORNIA 

ANDREW 

SMITH 

HALLIDIE: 


THIS  MANUAL  was  written  expressly   for   this  Company, 
and  the   matter    therein    contained    is    protected    by    a 
copyright.     Parties  infringing  will  be  prosecuted. 


TESTIMONIALS. 


I'.  S.  COAST  AND  GEODETIC  SURVEY, 

Sub  Office,  June  '2,   1SSS. 
Z  Co.,  S;\u  Francisco,  Cal. : 

Gentlemen— I  have  your  note  of  1st  June,  asking  me  to  express  an  opinion  of 
your  character  as  Mathematical  Instrument  makers. 

For  the  six  years  since  you  succeeded  to  the  business  of  Carl  Kahsskopff,  I  have 
been  so  Well  satisfied  with  the  character  of  your  workmanship  upon  the  various 
kinds  of  instruments  which  I  have  intrusted  to  your  care  that  I  have  seen  110  reason 
whatever  to  make  any  change. 

In  the  matter  of  new  instruments  and  novel  devices  you  have  fully  compre- 
hended the  wants  of  the  observer  and  have  intelligently  supplied  them. 

Very  respectfully, 

GEORGE  DAVIDSON. 


SAX  FRANCISCO,  May  14,  188S. 
A.  LIKT/  Co,,  San  Francisco: 

Gentlemen — My  acquaintance  with  your  establishment  for  the  manufacture  of 
Nautical  and  Field  Instruments,  and  the  knowledge  I  have  of  your  excellent  appli- 
ances for  such  work,  prompts  me  to  a  statement  thereof,  especially  as  you  have  fur- 
nished me  with  a  substantial  proof  of  your  workmanship  in  the  Transit  purchased 
of  you  some  months  ago.  This  instrument  has  since  been  constantly  used  in  im- 
portant surveys  in  an  extremely  rough  mountainous  country,  and  I  am  informed  by 
HIV  son,  who  has  been  operating  with  it,  that  it  is  in  every  respect  exceedingly  ac- 
curate in  all  operations  for  which  a  Transit  is  designed.  I  am  glad  to  express  my 
satisfaction  of  its  results  and  consider  it  a  high  recommendation  of  your  ability  to 
make  superior  instruments. 

Respectfully  yours, 

CALVIN  BROWN,  C.  E. 


BERKELEY,   CAL.,  May  24,  1888. 
A.  LIKT/  Co.,  San  Francisco,  Cal.: 

Gentlemen      Having  your  Transit  in  use,  I  take  pleasure  in  expressing  my  satis- 
faction.    1  am  pleased  particularly  with  the  Tripod  Coupling,  it  saving  much  time. 

Respectfully, 

11.  E.  Brsn, 

Civil  Engineer. 


SAN  JOSE,   CAL.,  June  4,  188S. 
A.  LIETZ  Co.,  San  Francisco: 

Gentlemen — It  is  with  great  pleasure  that  we  add  our  testimony  to  the  excel- 
lency of  your  Instruments.  The  two  Transits  and  one  large  Y-level  bought  of  you, 
a. re-  in  every  respect  as  good  and  serviceable  as  the  instruments  made  by  the  most 
reputed  of  eastern  tirms,  and  as  a  purely  California  or  home  production  deserve  the 
greatest  credit. 

The  graduations  made  on  your  own  graduating  machine  are  clear,  sharp  and 
exiict,  the  glasses  of  the  very  best  make  and  power,  and  the  needles  much  superior 
to  the  general  run  of  needles. 

Your  Tripod  Coupling  is  at  once  simple,  effective  and  safe,  and  we  consider  if 
better  than  any  other  coupling  used  by  other  makers. 

We  can  but  congratulate;  you  upon,  your  success  in  the  production  of  A  No.  1 
California  made  instrument,  and  heartily  recommend  you  to  the  profession. 

A' cry  truly  yours, 

HEHMAXX  BROS., 
Surveyors  and  Civil  Engineers. 


A.  LIKTX  Co.,  San  Francisco:  LA  P°RTE'  °AL"  Juiie  '"''  1S88- 


, 

Very  respectfully,  WM    SdirLn. 

TJ.  S.  Deputy  Mineral  Land  Surveyor. 

<  >\nr  R  ULWAY  AND  LAND  COMPANV 
A.  L,KT,  Co.,  San  Francis™,  Cal.  :  HOXOLO..U,  H.  I.,  December  1,  .802. 

Gentlemen—  In  1SHO  this  Company  bought  one  of  your  Transits  (No   »M)      Tf 
ms  been  m  nse  ,n  a  variety  of  work  and  gives  excellent'  satisfact  on      B  haf^em 


A"  the  "•""  are 

Yours  truly,  C,  H.  KLUEGEL,   Chief  Engineer. 


»      T  MAXWELL,    CAL.,    July    1.")      ]<S(H 

A.  LIKTX  Co.,  San  Francisco: 


1 


P  i      imo8/1^1!6  Tw  nSlt  maf6  f°r  me  by  y°U  is  a11  that  au  »«truinent  should  1,e 
i.,  ..huost  perfect.    Have  used  it  as  a  level  and  it  is  as  good  as  most  18-inch  ferelH 
1  am  now  making  a  survey  which  tests  its  qualities  verv  closely   and  the  result, 
obtained  are  excellent.      Stadia   measurements  of   distances  up  to  'seven  h,  u,     e 
feet  frequently  check  within  two  feet.     It  is  faster  and  cheaper  than  chaining 
Very  respectfully, 

A.  J.  BUTLER,  Civil  Engineer. 

Referring  to  Repairs  made  to  a  Leveling  Instrument. 

*    TTK  ^r  STOCKTON,  CAL.,  December  ]"»,  1391. 

A.  LTKTZ  Co.,  San  Francisco: 

Dear  Sirs-  '      "  The  work  was  well  nnd  satisfactorily  done  a;,d  chni  Kes 

moderate,  and  I  shall  be  pleased  to  rerommeud  you  to  any  friend.;  req.urm-  work  iu 
your  hue.  Very  truly  yours, 

E.  E.  TUCKER,  Civil  Engineer. 

.     T  SAN  FRAxnsco,   Dec.  23,  1301. 

A.  LIKTZ  Co.,  San  Francisco: 

Gentlemen—  It  gives  me  great  pleasure  to  certify  to  the  merits  of  Transit    No 
02   wl  u-h  I  purchased  from  you  in  August,  1890.     I  used  it  on  town  and  watex" 
works  surveys,  and  found  it  m  every  respect  a  first-class  instrument. 
Very  truly  yours, 

H.  S.  DAVIDSON,  Civil  Engineer. 

.  VIRGINIA,  NEV.,  October  2S,   IS^. 

A.   \A\:\-/,  Co.,  San  Francisco: 

(ieatleiuen—  We  take  pleasure  in  stating  that  the  instruments,   Transits    and 
Levels    which  you  have  furnished  us,  have  given  the  utmost  possible  satisfaction 

1  net  wo  transits  have  been  in  constant  use  for  three  years,  and  have  proven 
themselves  well  adapted  to  mountain  and  underground  work.     They  are  light  with- 
out weakness,  and  possess  an  extraordinary  degree  of  accuracy;  and,  furthermore 
•eiimst  acknowledge  the  promptness  you  have  displayed  in  filling  our  sometimes 
imperious  orders.     We  are,  gentlemen, 

Yours  very  respectfully, 

HF.LLMANN  k  HAIST,  Civil  and  Mining  Engineers. 

SAN  FRANCISCO.  October  29.   ].S9'2. 
A.  LIKT/  (  (».,  San  Francisco: 

.        Sirs—  I  have  used  the  Y-level,  No.  231,  made  by  you,  and  I  take  great  pleasure 
stating  that  it  has  given  entire  satisfaction.     It  is  absolutely  accurate  and  in  everv 
way  reliable. 

The  same  merit  can  be  claimed  by  your  Transits.     I  have  used  one  of  them  for 
e  months,  and  it  is  fair  to  state  that  I  have  never  handled  a  better  instrument. 
Yours  respectfully, 

FRANCIS  BRIDGKS,  Civil  Engineer. 


ASPEN-,  COLORADO,  October  31,  1892. 
A.  Lii.TZCo.,  Sun  Francisco: 

Sirs — It  is  with  great  pleasure  that  I  avail  myself  of  the  opportunity  presented 
me  to  say  a  kind  word  for  you  and  your  work.  The  Transit  made  by  you  and  used 
by  me  for  the  last  three  years,  I  am  certain  is  not  excelled  by  any  other  in  this  State 
MI-  elsewhere. 

In  convenience,  accuracy  of  centering,  and  graduation,  it  leaves  nothing  to  be 
desired.  That  it  is  to-day  in  as  good  a  condition  as  when  it  left  your  shop,  speaks 
well  of  its  construction  in  other  directions  than  accuracy  alone. 

Yonvs  truly. 

C.  S,  BATTERMAN. 


WOODLAND,  YOLO  Co.,  CAL  ,  November  3,  1892. 
A.  LIETZ  Co.,  San  Francisco: 

Sirs — Regarding  Level  No.  224,  which  I  purchased  of  you,  I  have  to  say  that  the 
year  I  have  owned  the  same  has  not  made  it  a  bad  name.  1  like  it  even  better  than 
I  did  when  I  purchased  it.  For  very  accurate  work  in  either  still  or  windy  weather 
1  have  never  vised  its  equal. 

Very  respectfully  yours, 

P.  N.  ASHLEY,  City  Engineer. 


AGENCY  SIERRA  BUTTES  GOLD  MINING  COMPANY,  LIMITED, 

SAN  FRANCISCO,  CAL.,  November  5,  1892. 
A.  LIETX  Co.,  San  Francisco: 

Dear  Sirs — I  take  pleasure  in  stating  that  the  Level  I  bought  of  you  is  a  first- 
class  instrument,  and  gives  perfect  satisfaction. 

Yours  respectfully,  WM.  JOHNS. 


WARDNER,  IDAHO,  December  8,  1892. 
A.  LIET/  Co.,  San  Francisco: 

<  rentlemen —  I  prefer  your  instruments  to  any  I  have 

seen  yet.  Respectfully  yours, 

JOSEPH  P.  KKANE. 

MODESTO  IRRIGATION  DISTRICT, 

LA  GRANGE  DAM,  January  11,  1S!K!. 
A.  LIKTZ  Co.,  San  Francisco; 

Gentlemen — I  take  pleasure  in  certifying  that  the  Transit  and  Level  bought  of 
you  three  years  ago  have  given  perfect  satisfaction,  the  adjustments  remaining  lo  tiger 
than  i'i  any  instrument  I  have  used  in  twenty-five  years  practice.  The  inverting 
telescopes  that  I  ordered  I  consider  superior' to  the  erecting  form,  and  for  hard  usage 
and  accurate  work  I  know  of  no  make  of  instrument  superior  to  your  Company's. 
Very  truly  yours, 

C.  D.  RHODES,  Civil  Engineer. 


CLIPPER  MILLS,  BUTTE  Co.,  CAL., 

February  3d,  1895. 

A.  LIETZ  Co.  : 

Gentlemen— You  would  hardly  believe  it,  but  I  have  used  your  transit  (No.  235)  for 
over  a  year  without  having  to  adjust  it,  as  it  has  retained  perfect  adjustment.  I  am  very 
careful  with  it. 

Yours  respectfully, 

H.  W.  CADWELL,  C.  E.,  E.  M. 

Sec.  Con.  Gentle  Anna  Mining  Co. 


EUREKA,  Feb.  ist,  1894. 
A.  LIETZ  Co.,  San  Francisco  • 

Gentlemen— I  have  had  the  pleasure  of  standing  behind  one  of  your  improved  levels, 
and  am  free  to  say,  "  she's  a  bird.'1' 

Very  respectfully, 

A.  T.  SMITH, 

U.  S.  Deputy  Surveyor 


< '  \M»KI.  VKI  \.  NKVVPA,  March  -JO,   1S!»;{. 
A.  Li  I:T/.  ( '<).,  San   Francisco: 

I)«'iii- .Sirs— I  am  highly  pleased  with  my. Transit  No.  2.">4,  made  l»y  yon.  which 
I  have  been  using  constantly  for  over  a  year.  It  is  thoroughly  reliable, 'and 
sider  it  one  of  the  best  in  use.  I  have  had  occasion  to  iiseit  a  great  deal  in  long  lev- 
eling practice,  and  my  limit  of  error  per  mile  has  never  exceeded  one-tenth  of  a  foot. 
It  is  a  combination  of  accuracy,  strength  and  lightness,  and  I  can  safely  recommend 
the  same  in  every  particular  to  the  engineering  profession. 

Yours  truly, 

JOHX  G.  BOOKER, 
1T.  S.  Deputy  Mineral  Surveyor  for  Nevada. 


LAKK  GUKKNO,   CAL.,  March  27,  KS!l.",. 
A.  LIF.T/  Co,,  San  Francisco: 

Gentlemen — Over  two  years  ago  I  purchased  one  of  your  18-inch  Y-levels.  It 
lias  been  in  constant  use  ever  since,  sometimes  subjected  to  very  severe  handling, 
and  I  desire  to  say  that  in  over  fifteen  years' practice  in  the  field,  using  instruments 
from  most  of  the  standard  makers,  yours  is  the  peer  of  any  in  design,  workmanship, 
action  and  all  of  the  attributes  of  a  first-class  instrument.  The  ease  of  manipula- 
tion and  constancy  of  adjustment  are  qualities  possessed  by  it  in  a  marked  degree, 
and  the  improvements  are  just  what  are  needed. 

In  short,  I  would  not  exchange  mine  now  for  an  instrument  of  the  same  grade 
from  any  other  maker.  I  expect  soon  to  lay  aside  all  others  and  to  use  none  but 
Lietz  instruments  in  all  branches  of  my  field  work  covered  by  them. 

It  is  a  great  pleasure  to  me  to  show  the  good  points  of  my  level  to  1113'  profes- 
sional brothers, 

Yours  respectfully, 

P.   M.  NORBOE, 

Civil  Engineer. 

JUNEAT,   ALASKA,  January  14,  1S93. 
A.  LT'KTX  Co.,  San  Francisco: 

Gentlemen — I  take  pleasure  in  stating  that  the  Mountain  Transit  purchased  from 
you  and  used  the  past  season  has  proven  excellent.  The  graduations  are  clean  and 
sharp.  In  regard  to  accuracy  of  the  graduation,  reliability  of  instrument  in  its  ad- 
justments—  the  tripod  not  only  simple  and  safe,  but  always  rigid  —  and  strength 
combined  with  lightness,  it  proves  entirely  satisfactory. 
Yours  truly, 

CHAS.   W.  GARSIDK, 

V.  S.  Deputy  Mineral  Surveyor  for 
Alaska,  and  Mining  Engineer 

SAN  JOSE,  CAL.,  June  17,   1SJK5. 
A.  LIKTZ  Co.,  San  Francisco: 

Sirs — In  regard  to  the  Simplified  Transit  bought  of  you  last  Fall,  permit  me  to 
say  that  I  have  used  it  continually  since  I  have  had  it  and  am  very  much  pleased 
with  it.  It  is  light,  handy,  easily  kept  in  adjustment  and  very  accurate.  In  short 
it  is  all  you  represented  it  to  be.  Will  be  pleased  to  recommend  the  instrument  to 
any  one. 

Very  truly,  X.  C.  PAKKKU. 


SAN  FRANCISCO,  March  loth,   1895. 
A.  LIETZ  Co.,  San  Francisco  : 

Gentlemen— In  the  prosecution  of  my  work  iu  opening  up  the  gravel  mines  of  t 
Playa  de  Oro  Mining  Company,  in  Ecuador,  South  America    we  had  occasion  to  use  one 
Lietz  transit,  one  Y-level,  and  one  dumpy  level. 

These  instruments  were  covered  with  water-proof  cloth,  and  despite  constant  rain  and 
exposure  incident  to  such  work,  and  in  such  a  wet  climate,  proved  thoroughly  satisfactory, 
and  1  can  most  strongly  recommend  them. 

Very  truly, 

MARK  B.  KF.KK, 

Civil  ami  Mining  Kngineer. 


ALUMINIUM  INSTRUMENT  TESTIMONIALS. 


N   TOSE,  CAL,  April  14*11,  [g 
A.  LIETZ  Co. 

Gentlemen — We  have  used  one  of  your  aluminium  mountain  transits  for  nearly  a  year, 
for  all  kinds  of  engineering  work,  in  places  exposed  to  great  heat  and  strong  winds,  and  find 
that  it  gives  us  better  results  and  more  satisfaction  than  heavy  transits  of  brass. 

We  find  that  its  small  weight  allows  on  easier  and  quicker  handling  in  rough,  mountain- 
ous places,  and  also  keeps  the  instrument  in  better  adjustment  and  more  free  from  accidents. 
In  fact,  we  don't  see  how  we  got  along  so  far  without  it.  and  why  engineers  and  surveyors, 
who  have  a  great  deal  of  mountain  work  to  do  and  carry  their  own  instrument,  insist  upon 
breaking  their  backs  with  a  25-pound  instrument,  when  they  can  get  one  which  weighs  7 
pounds,  and  does  the  work  fully  as  well. 

Respectfully  your*, 

HERRMANN    BROTHERS, 

Surveyors  and  Civil  Engineers. 

THE  MINEKAL  FARM  CONSOLIDATED  MINING  Co., 

Aspen,  Colorado,  April  30,  1895. 
A.  LIETZ  Co. 

Dear  Sirs — I  have  been  using  for  several  months  a  transit  of  your  make,  having  inclined 
standards. 

The  standards  and  telescope  are  of  your  aluminium  alloy,  and  give  perfect  satisfaction,  aj 
does  the  entiie  instrument,  which  is  of  special  make  throughout,  This  makes  two  transits  os 
your  manufacture  that  I  have  used. 

Yours  truly, 

C.  S.  BATTERMAN, 

Manager. 

SAN  FRANCISCO,  May  7th,  iS<)5. 
A.  LIETZ  Co. 

Dear  Sirs — Your  small  aluminium  transit,  No.  342,  proves  to  be  for  my  purposes  the 
most  convenient  and  satisfactory  instrument  I  have  yet  had  in  use. 

It  is  well  constructed  and  large  enough  for  all  ordinary  underground  and  surface  surveys, 
and  being  very  light  is  particularly  handy  for  rapid  work. 

Yours  truly, 

Ross  E.  BROWNE, 

Mining  and  Hydraulic  Engineer. 


UNIVERSITY  OF  CALIFORNIA, 
DEPARTMENT  OK  CIVIL  ENGINEERING  AND  ASTRONOMY. 

BERKELEY,  May  loth,  1895. 
A.  LIETZ  Co.,  San  Francisco. 

Gentlemen — The  plane-table  alidade  made  by  you  for  the  University  several  years  ago 
has  always  given  satisfaction. 

We  have  instruments  made  by  several  of  the  first-class  makers  in  this  country,  and  your 
alidade  compares  very  favorably  with  these. 

Very  respectfully, 

H.  I.  RANDALL, 

Instructor  in  Civil  Engineering, 
University  of  California. 


FERNDALE,  CAL.,  May  i5th,  1895. 
A.  LIETZ  Co.,  422  Sacramento  St.,  San  Francisco. 

Dear  Sirs — I  desire  to  state  that  I  am  well  pleased  with  your  small  aluminium  transit, 
which  I  purchased  from  you  about  two  years  ago.  It  is  small,  light  and  accurate.  Being  light 
it  is  particularly  adapted  for  mountain  field  work. 

There  is  no  question  but  that  the  aluminium  transit  is  the  one  for  the  engineer,  as  it  com- 
bines accuracy  with  lightness. 

Yours  respectfully, 

J.  A.  SHAW, 
Civil  Engineer  and  State  Licensed  Surveyor. 


BOARD  OF  STATE  FIARBOR  COMMISSIONERS, 
No.  10  California  St. 

SAN  FRANCISCO,  May  29th,  1895, 
A.  LIETZ  Co. 

Gentlemen — With  regard  to  the  aluminium  Y-level,  No.  304,  made  by  your  Company  for 
the  Board  of  State  Harbor  Commissioners,  I  take  pleasure  in  informing  you  that  it  has  given 
perfect  satisfaction,  and  I  will  state  that  if  it  were  not  possible  otherwise  than  by  paying 
double  the  price  of  the  old  style  brass  instrument,  I  would  willingly  do  so  in  order  to  get  one 
of  aluminium  manufacture. 

One  only  has  to  use  such  an  instrument  for  a  day  to  appreciate  the  difference. 
As  to  the  workmanship  of  the  above  level,  I  have  never  seen  better  in  my  experience  as 
an  engineer. 

Yours  respectfully, 

HOWARD  C.  HOLMES, 

Chief  Engineer. 

COUNTY  SURVEYOR'S  OFFICE,  SANTA  CRUZ  COUNTY. 

SANTA  CRUZ,  CAL,  June  i,  1895. 
A.  LIETZ  Co.,  San  Francisco. 

Gentlemen — I  take  great  pleasure  in  informing  you  that  I  have  used  the  aluminium  tran- 
sit, No.  320,  made  for  me  by  your  firm  about  a  year  ago,  on  all  kinds  of  city  and  county  work, 
and  find  it  in  every  way  the  equal  of  any  old  style  (bronze)  instrument  I  have  ever  used. 

It  holds  its  adjustments  very  well,  and  is  as  steady  in  the  wind  as  any  of  the  heavier 
instruments,  while  the  saving  of  labor  in  carrying  it  is  a  gain  that  cannot  be  over-estimated. 
I  think  that  when  it  has  been  once  thoroughly  tested  by  any  engineer,  he  will  abandon  his  old 
instrument  in  its  favor  in  every  instance. 

The  graduations  and  workmanship  are  in  all  respects  excellent. 

Yours  truly, 

CHAS.   L.  PIODA, 

Cily  Engineer. 

SAN  FRANCISCO,  Sept.  6th,  1894. 

I  have  had  occasion  to  use  a  small  aluminium  transit,  weighing  4%  pounds,  continuously 
for  about  six  months,  and  during  that  time  I  made  it  a  point  to  use  it  in  very  severe  and  stormy 
weather. 

I  recall  a  very  strong  breeze  near  a  California  mountain  town,  when  the  local  engineer  of 
the  work,  upon  which  I  was  then  engaged,  and  I  were  operating  together,  he  with  a  large 
transit  weighing  17%  pounds,  without  the  tripod.  Although  my  instrument  trembled,  its 
motion  was  not  a  violent  one,  and  I  could  still  read  a  stadia  rod  at  400  feet  distant,  when  it 
wns  utterly  impossible  for  him  to  manage  his  heavy  instrument  at  all.  The  amplitude  of  its 
vibrations  was  longer,  and  its  larger  superficial  area  gave  the  wind  more  surface  to  act  upon. 
Whenever  there  was  a  lull  in  the  wind,  my  transit  would  stop  trembling  at  once,  while  the 
heavy  instrument  would  continue  shaking  until  the  next  gust  would  strike  it  again. 

It  was  proven  to  our  satisfaction  that  the  small  aluminium  transit  was  by  far  steadier  than 
the  large  instrument,  although  the  latter  exceeded  it  13  pounds  in  weight  ;  it  was  not  as  top- 
heavy  and  the  wind  had  less  effect  upon  it. 

The  local  engineer  referred  to,  who  had  had  quite  an  objection  to  a  4%-pound  transit, 
became  fully  converted  to  aluminium  instruments  after  our  first  mutual  experience  in  the  wind, 
and  is  today  as  firm  a  believer  in  this  metal  as  I  am  myself. 

OTTO  VON  GELDFRN. 


MOUNTAIN  HOME,  ELMORECO.,  IDAHO,  Ma> 

THE  A.  LIETZ  COMPANY,  422  Sacramento  Street, 

San  Francisco,  Cal. 

Gentlemen  :  The  instruments  ordered  (Aluminium  Transit  and  Level)  came  to  hand  in 
due  course  of  time  all  O.  K.,  and  I  have  neglected  writing  you  on  account  of  press  of  busi- 
ness and  wanting  to  have  an  opportunity  to  test  the  transit  in  different  ways. 

What  can  I  say  in  praise  of  the  same  ?  Words  are  useless.  Money  could  not  buy  them 
if  I  could  not  replace  the  same.  I  think  that  will  give  you  an  idea  of  my  appreciation  of 
your  instruments. 

The  objection  was  raised  by  several  engineers  that  the  transit  would  shake  in  heavy 
wind.  I  know  better,  and  experience  is  the  best  of  knowledge.  Example  :  Having  a  placer 
claim  to  survey,  situated  upon  a  low  flat  island  in  Snake  River,  I  crossed  the  island  when  the 
waves  were  rolling  about  three  feet  high,  and  each  roller  helped  to  make  it  uncomfortable  by 
washing  into  the  boat  ;  commenced  at  lower  end  of  island,  stake  No.  I,  and  ran  around 
the  island  sixteen  courses  and  angle  corners,  and  closed  within  three  ft.  on  Stake  No.  I.  by 
calculation  Lat.  &  Dept.  Area  93  Acres.  Now  any  instrument  that  will  do  such  work  as 
that  in  a  windy  day  on  Snake  River  (and  it  just  know  show  to  blow  there),  I  think  is  beyond 
criticism. 

Having  many  levels  to  run  I  have  used  the  telescope  for  running  the  same  en  one 
•)f  our  canal  lines,  Preliminary  survey.  Ran  south  on  Twp.  line,  and  at  700  ft.  set 
-take  on  lower  side  of  ravine.  Returned  to  starting  point  and  ran  south-easterly,  cr<. 
ravine  in  narrow  place  for  flume,  and  ran  down  south  bank  of  ravine  to  stake  at  700  ft.  and 
closed  ;  looked  at, other  paper  on  which  I  had  taken  levels  on  Twp.  line  and  found  that 
readings  were  the  same  for  that  point.  Elevation  9.40  ft.  Such  an  instrument  will  answer 
for  me  ;  those  who  want  a  better  one  can  hunt  for  it. 

The  level  is  a  Daisy  and  meets  all  requirements. 

An  Engineer  or  Surveyor  can  carry  it  all  day  and  not  feel  like  leaving  it   wherehe  stops 
at  night.     I  would  recommend  the  same  to  any  one  of  my  profession,  and  advise   the; 
go  and  do  as  I  did  :  buy  the  same  from  A.  Lietz  Company. 

Yours  Respectfully 

SAMUEL  G.  RHODES, 
U.  S.  Dep't.  Surveyor  for  Idaho. 


TESTIMONIALS 


REFERRING     TO    THE 


NEW  CYCLOTOMIC  TRANSIT 

(PATENTED   MARCH   1896) 
MADE    BY 

A.    LIETZ    CO. 

MANUFACTURES   OF    SCIENTIFIC    INSTRUMENTS 

422  SACRAMENTO  STREET 

SAN  FRANCISCO,  CAL. 


EXPLANATORY     NOTE. 


IX  the  following  pages  we  present  a  few  testimonials,  referring  to  our 
Cyclotomic  Transits.  We  have  chosen  three  to  each  grade  of  instrument, 

although  we  might  have  supplemented  this  number  by  many  more  of  the 
same  character,  were  we  not  of  the  opinion  that  a  repetition  of  the  same 
statement  is  useless. 

There  is  no  doubt  that  the  Cyclotomic  Transit  is  a  successful  innovation. 
We  were  fully  aware  of  this  when  we  began  building  these  instruments,  but 
we  have  thus  far  withheld  all  expression  of  opinion  regarding  them,  deeming 
it  advisable  to  allow  sufficient  time  to  test  their  qualities  in  every  way  in  actual 
field  practice.  During  the  last  two  and  a  half  years  quite  a  number  of  in- 
struments of  this  character  have  been  sold  by  our  Company,  and  the  time  has 
come  when  we  are  prepared  to  substantiate  the  claims  we  originally  made. 

We  beg  to  refer  onr  readers  to  the  following  testimonials,  and  will  ask 
them  to  compare  these  flattering  expressions  with  the  statements  made  by  us 
in  our  first  description  of  the  Cyclotomic  Transit. 


to    .... 
Migli-Graclc    Cyclotomic    Transits 

No.   18 


I'ltlTV    Ml.MNl.    AM'    PKYKI.Ol'MKXr    Co. 

Prescott,  Arizona,  July  5th,  1897. 

A.  MET/,  co. 

422  Sacramento  Street,  San  Francisco. 

Gentlemen:— The  Cyclotomic  Transit,  No  375,  purchased  from  you 
one  year  ago,  has  been  in  constant  use  in  a  variety  of  work  by  myself,  in- 
cluding inside  and  outside  mine  surveys,  mill-work,  road  grading,  stadia 
measurements,  topographic  surveys,  etc  I  have  had  no  trouble  with  it,  but 
have  found  it  wholly  reliable  in  complicated  shaft  and  tunnel  work  and  in 
every  way  as  accurate  as  other  styles  of  instruments  heretofore  used  by  me. 
In  all  particulars  in  which  you  claim  superiority,  as  to  convenience,  stability 
and  non-liability  to  injury  from  rough  usage,  my  experience  coincides  fully 
with  your  statements.  My  transit  was  set  up  some  months  ago  in  a  very 
unstable  position  on  a  mountain  slope,  and  fell  in  such  manner  as  to  give  it 
a  jar  sufficient  to  ruin  one  of  the  old-style  instruments ;  but  I  have  had  it  in 
use  constantly  since  that  date,  on  work  requiring  strict  accuracy  The  only 
damage  from  the  accident  was  a  very  slight  throwing  out  of  adjustment  of 
the  horizontal  limb  at  one  point,  which  was  readily  corrected. 

I  regard  the  cyclotomic  principle  as  one  of  the  most  important 
improvements  of  the  age,  as  it  is  one  of  the  most  simple  when  one  is  once 
accustomed  to  its  manipulation.  Yours  very 'respectfully, 

(Signed)     THEO.  B.  COMSTOCK. 

1614  Buoni:i;icK  STUF.KT, 
San  Francisco,  Cal.,  July  16th,  1897. 
A.   MET7  CO., 

Dear  Siis; — I  take  pleasure  in  sending  you  a  few  lines  in  reference 
to  the  "Cyclotomic  Transit,"  No.  378,  which  I  purchased  from  you  in  August 
of  last  year;  it  lias  given  perfect  satisfaction.  Not  only  is  it  more  steady  in 
high  winds  than  any  instrument  I  have  used  before,  but  it  keeps  in  better 
adjustment. 

The  instrument  is  accurate  and  of  easy  and  rapid  manipulation.  Its  chief 
charm  is  its  lightness,  which  in  no  way  detracts  from  its  usefulness. 

Yours  truly, 

[Signed]         L.  S.  Ql'IMBY. 


OKFICK  <>K   P.   N.   ASHLKY, 

County  Surveyor,  Volo  Comity. 

city  Kngineer,  Woodland. 

State  Licensi-d  Surveyor  for  California. 

Woodland,  California,  July  24th,  1897. 
A.  L1ETZ  CO., 

San  FrancisQp. 

Gentlemen: — Cyclotomic  Transit,  No.  37G,  bought  from  you  last  winter, 
has  proven  very  satisfactory  to  me.  Graduations  are  clear  and  easily  read, 
instrument  steady,  and  the  solar  attachment  gives  very  close  definitions  to 
true  directions  of 'lines  run,  thereby  obviating  the  necessity  of  keeping  up  long 
and  expensive  transit  deflections  on  extended  surveys  in  brushy  country. 

Very  respectfully 

[Signed]        P.  N.  ASHLEY. 


Referring  to 


High-Grade    Cyclotomic    Transits 

No.  18a 


DKI'ARTMEXT  OF  Prnuc 

Office  of  the  Commissioner.  j| 

Mount; Vernon,  New  York,  May  25th,  1807. 
A.  L1ETZ  CO., 

422  Sacramento  Street,  San  Francisco. 

Gentlemen:— I  take  pleasure  in  saying  the  Cyclotomic  Transit  Theodolite 
fully  meets  my  expectation.  It  does  all  the  work  of  a  larger  and  heavier  one 
and'  is  so  much  less  burdensome  to  carry,  the  cyclotomic  feature  is  quite  as 
readily  manipulated  as  the  double  center  and  in  every  way  equal,  unless 
repetition  of  angles  is  required. 

My  assistants  who  use  the  instrument  are  delighted  with  it,  while  I 
regard  the  devices  for  attaching  to  tripod  and  shifting  center  as  excellent.  It 
is  also  in  all  other  respects  an  up-to-date  machine. 

Yours  respectfully, 
[Signed]        F.  S.  ODELL,  Commissioner. 


AV.  AV.  W.\<;<;OXKK, 

('.  S.  Keputy  Mim-ntl  Surveyor 
and  Civil  Engineer. 

Nevada  City,  Calif.,  July  3d,  1897. 

A.   LIETZ  CO., 

San  Francisco. 

Gentlemen:  —  Your  small  aluminium  Cyclotomic  Transit,  No.  464,  pur- 
chased by  me  last  March  has  given  good  satisfaction.  It  is  especially  adapted 
for  rapid  mountain  work,  and  in  surveys  through  upraises  and  cramped 
openings  in  mines,  where  a  heavy  instrument  is  inconvenient  and  difficult  to 
handle.  With  surface  work  I  have  had  no  trouble  in  making  closings  of 
1  in  oOOO.  Very  truly, 

[Signed]        W.  AV.  WAGGONER. 


CONTINENTAL  M INK, 
Globe,  Arizona,  July  10th,  18(.»7. 
A.    LIETZ  CO., 

San  Francisco. 

Gentlemen:  —  In  answer  to  your  favor  of  the  1st  inst.,  I  may  say  that  I 

am  perfectly  satisfied  with  your  Cyclotomic,  Transit,  No.  476  which  makes  a 

strong  instrument  very  well  adapted  to  ordinary  mining  une,  and  which  after 

u  little  practice  ran  be  handled  quicker  than  the  usual,  or  repetition  transit. 

Very  truly  yours, 

[Signed]        EDMOND  DE  STOUTZ, 
For  the  North  American  Exploration  Co.,  Ltd. 


Referring  to    .... 

Cyclotomic    Reconiioissance    Transits 

No.  18b 


San  Francisco,  September  2nd,  1896. 
A.  LIETZ  CO., 

I  send  you  to-day  the  Cyclotomic  Transit,  No.  410,  (Reconnoissance)  and 
beg  you  to  clean  it,  because  it  has  made  long  surveys  with   rain   and  dust. 
Daring  these  operations,  I  could  verify  the  perfect  accuracy  and  the  easy  use 
of  the  transit,  and  I  have  the  pleasure  to  mark  my  satisfaction. 
With  my  distinguished  civilities, 

[Signed]        JE.  RIGAUB, 
Ancien  ingenieur  en  chef  des  Mines. 
Ancien  directeur  de  IV-cole  des  mines  d'  Alais. 


San  Francisco,  Cal.,  July  2d,  1897. 
MESSRS.  A.  LIETZ  CO. 

422  Sacramento  Street,  San  Francisco. 

Gentlemen: — Replying  to  your  inquiry  of  the  1st  inst,  I  am  pleased  to 
say  that  the  "Cyclotomic"  Reconnoissance  Transit  purchased  from  you  by 
the  California  Wire  Works,  some  nine  months  ago,  has  given  entire  satisfac- 
tion. Yours  very  truly, 

[Signed]        E.  I.  PARSONS,  C.  E. 


Merced  Falls,  July  5th,  1S!»7. 
A.  LIETZ  CO., 

San  Francisco. 

Gentlemen: — The  Cyclotomic  Reconnoissance  Transit,  made  for  me  last 
winter,  1  regard  as  an  excellent  instrument  for  the  general  work  of  a  surveyor 
in  rough  regions  It  is  very  light  and  convenient,  and  sufficiently  accurate  for 
all  but  the  rinest  work.  Respectfully  yours, 

[Signed]        G.  P.  KELSEY. 


FOR     DESCRIPTION 
OF     THK • 

CYCLOTOMIC    TRANSIT 

AND 

PRICE     LIST 

Pages  121-126  and 


THIRD    EDITION 

OF  THE 

MANUAL 


OF 

Modern  Surveying  Instruments 


AND    THEIR    USES, 

CONTAINING  USEFUL  INFORMATION  FOR  THE 

L  ENGINEER  AND  SURVEYOR. 
UNIVERSITY  ( 

J 

TOGETHER    WITH   A 

CATALOGUE  AND  PRICE    LIST 

OF 

SCIENTIFIC    INSTRUMENTS, 

PARTICULARLY  THOSE  OF  THE  CIVIL  ENGINEER  AND  SURVEYOR, 

MADE   BY 

THE  A.  LIETZ  COMPANY, 

422    SACRAMENTO    STREET, 

SAN  FRANCISCO,  CALIFORNIA. 

1899. 

PRICE,  50  CENTS 

PUBLISHED  BY  THK  COMPANY  WRITTEN  AND  EDITED.  BY  OTTO  VON  GELDERN. 

COPYRIGHTED. 


ESTABLISHED     1882. 


NOTICE. 


T 


HIS  Manual  supersedes  the   former  edition  of  our  cata- 
logue, and  is  carefully  revised  and  corrected  to  date. 


The  articles  manufactured  by  this  Company  are  quoted 
at  prices  consistent  with  the  quality  of  workmanship,  and  no 
deductions  will  be  made.  We  endeavor  to  place  before  the 
public  an  equivalent  of  the  very  best  that  can  be  obtained  in 
this  country,  without  imitating  in  shape  or  design  any  make 
whatever.  All  our  articles  are  of  the  most  recent  standard, 
with  every  known  improvement. 

Distant  purchasers  will  please  remit  by  check,  money 
order,  or  registered  letter,  or  order  C.  O.  D. 

According  to  the  rules  of  Wells,  Fargo's  Express  Com- 
pany, a  surveying  instrument,  carefully  placed  in  its  case  and 
in  a  packing  box,  is  shipped  as  merchandise  and  charged  at 
"  single  rate."  "  Three  rates"  will  be  charged  if  this  precau- 
tion be  not  taken.  The  customer  should  not  omit,  therefore, 
to  pay  strict  attention  to  this  rule  of  the  Express  Company, 
and  avoid  unnecessary  overcharges. 

Packing  boxes  are  furnished  by  us  at  a  nominal  rate. 


PREFACE. 


"YTTE  issue  this  book  for  the  benefit  of  the  engineering  pro- 
fession. This  statement  is  justified  in  every  way. 
Comparatively  few  are  aware  that  scientific  instruments  are 
made  on  the  Pacific  Coast,  and  if  it  were  generally  known,  it 
would  require  considerable  effort  to  remove  the  doubt,  whether 
our  home  industry  work  could  possibly  compare  with  that  of  the 
Eastern  maker.  It  is  difficult  to  see  why  such  disparaging  opin- 
ions should  exist,  but,  as  they  do,  we  have  endeavored  to  remove 
that  prejudice  by  publishing  a  careful  description  of  what  we 
are  able  to  produce  —  not  only  that,  but  just  how  we  produce  it 
—  so  that  the  public  may  have  that  confidence  which  an  earnest 
effort,  honest  labor  and  skilful  handiwork  deserves.  We  benefit 
the  profession  if  we  can  accomplish  this  object. 

Considerable  information  has  been  published  herewith. 
The  details  of  every  instrument  are  carefully  enumerated,  and 
the  functions  of  every  >part  minutely  described,  so  that  the  book  really 
becomes  a  pocket  companion  for  the  engineer. 

And  we  would  advise  our  patrons  to  consult  this  Manual  frequent- 
ly;  it  will  be  noticed  that  every  adjustment  and  make-shift  repair  has 
found  special  mention  and  careful  consideration.  Refer  to  the 
index,  and  look  up  the  subject  before  undertaking  anything 
that  may  lead  to  more  serious  trouble  afterwards. 

The  Manual  is  divided  into  four  parts. 

Part  I  contains  a  full  description  of  our  establishment  and 
its  methods  of  working. 

Part  II  deals  with  the  manufacture  of  Engineering  Instru- 
ments, their  uses,  repair,  adjustments  and  proper  methods  of 


167616 


IV 

handling  them,  so  that  they  may  retain  their  fine  qualities  for 
an  indefinite  time. 

Part  III  contains  a  number  of  professional  papers,  written 
by  well-known  men.  They  furnish  considerable  information 
of  value,  and  we  would  ask  you  to  give  them  your  attention. 
The  article  on  Stadia  Surveying  has  been  written  for  this 
Manual,  and  from  it  this  method  of  measuring  may  be  readily 
acquired  by  any  surveyor.  Noexpense  has  been,  spared  to  make 
these  papers  complete  in  every  particular,  including  useful 
tables  that  cannot  be  had  in.  any  other  book  of  this  kind. 

Part  IV  has  a  full  price  list  of  every  article  manufactured 
and  sold  by  the  Company.  The  customer  may  find  any  infor- 
mation, and  arrange  his  purchase  to  the  money  he  may  desire 
to  spend. 

Nothing  more  need  be  said  under  this  head.  Whether  we 
deserve  success  is  now  left  with  the  profession;  we  will  guar- 
antee to  do  our  share  as  carefully  and  honestly  as  the  Manual 
states  it  to  you.  To  those  who  are  yet  strangers  to  our  work,  we 
take  this  opportunity  of  asking  them  to  give  us  a  fair  trial. 

There  is  another  point  upon  which  we  desire  to  make  a  few 
statements,  which  are  more  particularly  addressed  to  the  general 
public,  however. 

The  ordinary  purchaser  is  not  aware  of  the  fact  that  it  is  far  more 
satisfactory  to  go  at  once  to  the  manufacturer  when  an  optical,  nauti- 
cal or  surveying  instrument  is  required.  A  regular  practitioner,  who 
knows  what  he  wants,  may  order  by  means  of  the  catalogue  of  any 
dealer,  but  there  are  frequent  occasions  when  the  farmer,  the  grader, 
contractor,  street  builder,  forester,  irrigator  or  mountaineer  wants  an 
instrument  for  some  special  purpose  ;  and  in  such  case  it  is  always 
better  that  he  should  go  to  a  reputable  instrument-making  firm  at  once, 
instead  of  making  his  inquiries  of  the  dealer,  who  can  not  possibly  un- 
derstand his  wants. 


There  is  nothing  unreasonable  in  calling  the  attention  of  the 
public  to  this  fact.  We  deal  in  articles  with  the  manufacture  and 
functions  of  which  we  are  fully  conversant.  Education,  training 
and  experience  have  given  us  advantages  over  the  mere  dealer, 
which  it  is  not  only  our  privilege  but  our  duty  to  proclaim. 

THE  A.  LIETZ  CO. 


INTRODUCTION. 


WHEN  the  present  business  of  manufacturing  scientific  instru- 
ments was  established  in  San  Francisco  some  fifteen  years 
ago,  it  was  realized  that  in  order  to  compete  with  other  makers  it 
would  be  necessary  to  produce  an  article  equal  to  the  very  best 
Eastern  or  European  manufacture.  And  in  no  other  branch  of  the 
business  did  this  become  more  apparent  than  in  that  devoted  to  the 
construction  of  instruments  for  the  civil  engineer.  With  this  ob- 
ject constantly  in  view,  the  present  establishment  has  been  gradu- 
ally built  up  by  Mr.  Adolph  Lietz,  and  it  has  now  gained  the  con- 
fidence and  the  favor  of  our  Pacific  Coast  practitioners. 

It  is  with  great  pride  that  the  firm  looks  upon  its  success,  for 
it  has  given  to  the  Coast  an  industry  that  in  results  is  not  excelled 
anywhere.  The  motto  has  been:  "WE  CAN  BUILD  ANYTHING  IN  OUR 
LINE  'OUT  HERE'  AS  WELL  AS  THEY  DO  EAST,  AND  WHY  NOT?" 
And  with  strict  devotion  to  the  profession,  and  straightforwardness 
in  commercial  dealings,  the  firm  has  proven  the  maxim  a  sound  one. 

In  order  to  expand  the  scope  of  this  establishment  a  stock  com- 
pany was  organized  in  March  1892,  known  as  '  'The  A.  Lietz  Com- 
pany," and  in  the  Board  of  Directors  of  this  Company  Mr.  Lietz 
associated  with  himself  men  of  known  professional  experience, 
both  practically  and  theoretically.  Three  civil  engineers,  Mr.  C.  E. 
Grunsky,  Mr.  D.  C.  Henny  and  Mr.  Otto  von  Geldern,  all  well  known 
on  fche  Coast,  represent  the  advisory  board  of  the  Company,  for 
upon  their  suggestions,  based  upon  practical  experiences,  the 
various  engineering  instruments  in  use  by  the  profession  have 
been  brought  up  to  that  modern  standard  of  excellence  requir- 
ed of  an  instrument  at  the  present  time.  For  this  is  also  a  policy 
of  the  company:  to  adopt  at  once  any  form  of  improvement  which, 
after  a  careful  consideration,  has  shown  itself  worthy  of  adoption. 


vii 


Experiments  incorporating  new  ideas  are  never  postponed,  but 
at  once  carried  out  and  tested  as  to  possible  merit. 

In  this  wise  the  present  forms  of  theodolite,  transit,  level, 
etc.,  have  been  evolved;  and  it  is  the  purpose  of  this  illustrated 
catalogue  not  only  to  show  its  readers  the  detailed  construction 
of  the  instruments,  but  also  to  dwell  upon  individual  parts,  and 
to  explain  the  methods  of  construction  and  the  appliances  that 
are  used  in  creating  a  modern  instrument  of  precision. 

The  incorporated  Company  announced  its  new  departure 
to  the  public  in  a  circular  letter  dated  March  1st,  1892,  from  which 
we  beg  to  publish  the  following  extracts  : 

We  take  pleasure  in  informing  the  public  that  the  well-known  firm  of  A.  Lietz  & 
Co.  has  been  incorporated  as  a  stock  company,  which  will  be  known  as 
"THE  A.  LIETZ  COMPANY." 

The  names  of  the  men  associated  with  this  enterprise  are  a  guarantee  that  the  busi- 
ness will  be  conducted  on  a  sound  basis,  that  the  articles  manufactured  will  be  of  the  best 
quality,  and  that  all  work  done  by  the  Company  will  be  of  superior  workmanship. 

The  Lietz  surveying  instruments  are  too  well  known  to  require  special  mention. 
We  shall  endeavor  to  please  our  customers,  and  will  give  them  the  assurance  that  our 
constant  aim  shall  be  to  produce  instruments  of  precision  with  every  improvement 
known  to  the  art. 

We  pride  ourselves  on  the  established  fact  that  the  firm  has  succeeded  in  develop- 
ing a  HOME-MADE  engineering  instrument  that  is  first-class  in  every  particular,  and 
especially  designed  in  its  details  for  the  requirements  of  the  Pacific  Coast.  We  do 
not  hesitate  to  say  that  this  instrument  will  be  found  SUPERIOR  to  ninety  per  cent,  of 
the  imported  articles,  in  every  respect. 

We  should  deem  it  a  particular  favor  if  our  patrons  would  call  upon  us  personally, 
so  that  we  may  show  them  the  articles  manufactured,  and  the  particular  merit  claimed 
in  each  individual  case.  We  have  closely  followed  the  wants  of  the  engineer,  and  have 
constantly  endeavored  to  supply  his  needs  as  they  became  apparent  from  time  to  time. 
In  this  we  shall  continue  under  the  advice  of  our  directors,  three  of  whom  are  practical 
field  engineers  well  known  to  the  profession  on  the  Pacific  Coast. 

We  are  also  in  the  position  to  manufacture  and  repair  scientific  instruments  of  any- 
character  for  astronomical,  philosophical,  nautical  and  similar  purposes. 

Particular  attention  is  called  to  our  graduating  machine,  which  is  of  the  most  ap- 
proved pattern,  enabling  us  to  graduate  circles  or  arcs  to  any  degree  of  minuteness; 
and  to  our  new  adjusting  apparatus,  where,  by  means  of  collimators,  adjustments  are 
possible  that  cannot  be  obtained  in  the  field,  or  by  any  other  method,  with  the  accuracy 
and  refinement  required  of  first-class  instruments. 

Repairs  will  have  our  personal  supervision,  and  will  be  promptly  executed. 

We  shall  keep  on  hand  an  assortment  of  field  and  office  supplies  for  the  Civil, 
Mining,  Irrigation,  Hydraulic,  Military  and  Mechanical  Engineer,  and  most  respect- 
fully solicit  the  patronage  of  our  friends  and  the  public. 

Adding  our  thanks  for  past  favors,  we  remain, 

Respectfully  yours,  THE  A.  LIETZ  CO, 

SAN  FRANCISCO,  CAL.,  March  1,  1892. 


To  OUR  PATRONS. 


We  would  call  your  attention  to  our  complete  price  list  in  Part 
IV.  After  reading  the  information  given  in  Part  II,  the  customer 
will  be  convinced  that  the  price  of  an  article  should  not  govern  his 
purchase.  High-grade  engineering  work  requires  a  first-class  tool  to 
work  with,  and  the  matter  of  twenty  dollars,  more  or  less,  in  original 
outlay  will  amply  pay  for  itself  in  the  end. 


NOTICE!! 

It  has  been  asserted  that  tlie  VARIA- 
TION OF  THE  COMPASS  cannot  be 
laid  off  accurately  upon  a  LietsK  Tran- 
sit. "We  wish  to  call  especial  attention 
to  the  fact  that  the  VARIATION  MAY 
BE  LAID  OFF  TO  THE  MINUTE 
WITH  MORE  THAN  ORDINARY 
PRECISION. 

For  Method  see  pa^e  24. 


CAUTION! 


In  order  to  prevent  changes  in  the  magnetism  of  the  Needle,  do 
not  bring  your  transit  instrument  into  juxtaposition  with  objects  gener- 
ating or  transmitting  strong  electric  currents,  such  as  dynamos,  electric 
car  lines,  etc.  If  absolutely  necessary  to  be  within  the  influence  of 
strong  currents,  allow  the  needle  to  swing  freely.  Avoid  riding  in 
electric  cars  with  your  transit,  if  possible. 


See  the  description  of  our  CYCLO- 
TOMIC  TRANSIT,  the  Fin  de  Siecle 
instrument,  combining  the  greatest 
simplicity  with  the  greatest  rigidity 
and  absolute  completeness  in  work- 
ing parts.  An  innovation  in  the  in- 
strument-maker's art. 


I, 


.   DESCRIPTION  OF  THE  ESTABLISHMENT, 


THE  A.  LIETZ  COMPANY, 

SAN  FRANCISCO. 


I. 


DESCRIPTION  OF  THE  ESTABLISHMENT. 


The  location  of  the  workshop  and  salesroom  occupies  the 
upper  or  third  floor  of  the  building  on  the  northeast  corner  of 
Sansome  and  Sacramento  streets,  San  Francisco. 

The  various  departments  of  the  business  consist  of  the 
shop,  the  business  office,  the  foundry,  the  graduating  and  ad- 
justing room,  and  the  special  nautical  department. 

In  the  large  and  commodious  workshop  a  number  of  busy 
lathes,  driven  by  steam  power,  are  going  from  morning  until 
evening,  and  at  long  workbenches  under  the  light  -of  a  dozen 
windows  the  workmen  are  employed  —  some  in  the  exclusive 
manufacture  of  new  instruments  for  the  market,  others  in  the 
repair  of  such  that  are  constantly  received  from  all  parts  of  the 
country.  No  expense  has  been  spared  to  add  to  the  shop  every 
mechanical  facility  to  increase  its  efficiency. 

Plate  I  is  an  illustration  intending  to  show  the  interior 
view  of  the  shop  as  seen  from  the  business  entrance. 

Directly  in  front  of  the  work-room  is  the  part  devoted  to 
the  commercial  interests  of  the  establishment.  A  number  of 
large  glass  showcases  contain  articles  on  sale,  consisting  of  new 
theodolites,  transits,  Y-levels,  dumpy  levels,  microscopes,  tele- 
scopes, hand  levels,  barometers,  thermometers,  sextants,  com- 
passes, drawing  instruments  of  all  descriptions,  tape  lines, 
scales,  planimeters,  chains,  odometers,  pedometers,  field  glasses, 
mining  apparatus,  mechanical  contrivances,  etc.,  etc. 

In  the  rear  of  the  office  is  the  foundry,  which  has  recently 
been  added  to  the  establishment.  It  is  more  particularly  used 


THE    A.    LIETZ    COMPANY. 

and  designed  for  aluminium  castings,  with  which  metal  the 
company  has  lately  made  many  experiments,  and  out  of  which 
the  remarkably  light  transits  and  levels  have  been  made,  which 
shall  be  noticed  more  in  detail  further  on. 

From  the  foundry  a  stairway  leads  to  the  roof,  upon  which 
the  ranges  for  testing  telescopes  and  other  useful  measuring 
and  accessory  apparatus  are  located. 

The  most  vital  part  of  the  establishment  is  the  graduating 
and  adjusting  department,  which  contains  the  large  circular 
dividing  engine  for  graduating  circles  and  plates  to  any  re- 
quired degree  of  precision.  It  also  contains  certain  valuable 
apparatus  for  testing  the  individual  parts  of  an  instrument, 
and  the  mural  collimators  for  adjusting  an  instrument  with  an 
amount  of  exactness  that  cannot  be  obtained  in  the  field  under 
the  very  best  circumstances.  In  plate  II  is  seen  the  end  of 
one  of  the  collimator  levels  as  photographed  with  the  interior 
view  of  the  graduating  and  adjusting  room.  Plate  VI  shows 
the  method  employed  in  adjusting  by  means  of  collimators. 
It  is  so  apparent  to  the  eye  that  it  will  hardly  require  any 
further  explanation.  With  it  all  the  necessary  adjustments  are 
at  once  readily  and  precisely  accomplished. 

Plate  III  shows  the  large  circular  dividing  engine,  built  by 
the  firm,  with  which  all  the  graduations  are  made.  The  Com- 
pany has  been  frequently  complimented  on  the  absolute  ac- 
curacy of  its  divisions,  and  on  the  sharpness  with  which  the 
vernier  contact  may  be  observed  under  a  magnifying  power. 

In  a  paper  read  before  the  Technical  Society  of  the  Pacific 
Coast  on  December  5th,  1890,  entitled:  Some  Practical  Hints  on 
Hoiv  to  Tell  a  Good  Surveying  Instrument,  Mr.  Lietz  brought  to 
the  notice  of  the  Society  his  experiences  in  graduated  circles, 
wherein  he  refers  to  the  true  line  as  made  by  a  proper  cutting 
apparatus,  and  as  to  what  constitutes  a  good  and  sharply  defined 
line.  This  professional  paper  has  been  added  herewith,  and 
may  be  found  in  full  in  Part  III  of  this  catalogue.  It  is  repub- 
lished  with  the  Society's  permission,  and  the  reader's  attention 
is  called  to  this  short  resume  of  the  instrument  maker's  art. 

Plate  IV  shows  a  centering  apparatus  for  testing  the 
accuracy  of  graduations,  and  also  the  Company's  small  dividing 


0  MODERN    SURVEYING    INSTRUMENTS, 


apparatus  for  linear  graduations.  The  former  is  one  of  the 
most  useful  accessories  of  the  graduating  department,  where- 
with the  most  crucial  tests  of  the  locus  of  the  center  of  the 
graduated  plate  are  made. 

Plate  V  has  the  level  tester,  which  is  used  in  determining 
the  degree  of  sensitiveness  of  the  curvature  of  the  glass.  With 
this  apparatus  it  is  possihle  to  obtain  an  accurate  value  of  a 
division  of  the  graduated  bubble  in  seconds  of  arc. 

The  same  plate  shows  also  an  apparatus  used  for  determin- 
ing the  influence  of  the  metal  on  the  magnetic  needle. 

The  NAUTICAL  DEPARTMENT  has  been  made  a  special  feat- 
ure of  the  establishment,  which  possesses  the  facilities  for 
manufacturing  and  repairing  compasses,  sextants,  logs,  and  all 
the  usual  mathematical  appliances  of  the  navigator.  The  shop 
has  adequate  means  for  repairing  mercurial  and  aneroid  bar- 
ometers of  the  finest  grade;  an  air-pump  for  testing  an  aneroid 
to  any  degree  of  atmospheric  pressure,  in  connection  with  a 
standard  mercurial  instrument,  is  one  of  the  features  of  this 
department. 

We  are  able  to  extend  these  barometrical  examinations  and 
repairs  to  those  of  the  very  finest  and  most  delicate  make,  includ- 
ing the  beautiful  Goldschmid  Aneroid, with  which  such  remark- 
able hypsometric  results  have  been  obtained  in  the  Alpine 
regions  of  Switzerland,  to  which  reference  will  be  made  in  the 
third  part  of  this  catalogue. 

Another  branch  of  the  business  is  that  exclusively  devoted 
to  the  making  of  mechanical  devices,  of  models,  or  contrivances 
requiring  accurate  and  delicate  fittings.  Work  of  this  character 
has  been  done  in  the  electrical  line,  by  building  apparatuses 
intended  for  a  practical  or  scientific  purpose.  Similarly  has 
this  field  been  extended  to  philosophical,  meteorological,  astro- 
nomical, photographic,  optical  and  other  apparatus,  from  the 
most  simple  to  the  most  delicate  in  character. 

The  Company's  IMPORTATIONS  of  lenses  and  spirit-levels 
are  of  the  very  best  European  make. 

Mr.  Lietz  spent  several  months  on  the  European  continent  recently, 
in  order  to  obtain  the  finest  articles  in  this  line,  and  there  is  every 
reason  to  congratulate  the  firm  upon  the  success  of  this  investigation. 


PLATE  IV. 


A.  LIETZ  CO.,  SAN  FR \NCISCO,  CAL. 


CENTERING  APPARATUS  FOR  TESTING  GRADUATIONS, 
IN  THE  ADJUSTING  ROOM. 


LINEAR     DIVIDING     ENGINE 

IN    GRADUATING    U 


g  THE    A.    LIETZ    COMPANY. 

Reference  will  again  be  made  to  these  parts  in  the  description 
of  the  instruments. 

The  object  has  been  to  manufacture  every  detail  in  the 
San  Francisco  shop;  but  those  parts  which  cannot  be  made, 
and  which  are  generally  imported  by  the  best  makers,  must  be 
of  the  very  finest  quality  obtainable,  and  for  this  particular 
purpose  Mr.  Lietz's  recent  European  trip  was  undertaken. 

It  would  be  tedious  to  our  readers  to  enumerate  every  de- 
tail of  the  numerous  appliances  made  use  of  in  the  manufactur- 
ing and  repairing.  Enough  has  been  shown  to  convince  any 
fair-minded  man  that  this  Company  is  enabled  to  manufacture 
instruments  as  well  as  any  Eastern  firm.  And  upon  this  fact 
we  wish  to  lay  particular  stress.  WHY  SHOULD  ouu  ENGINEERS 
SEND  EAST,  WHEN  THEY  CAN  DO  AS  WELL  AT  HOME?  By  examin- 
ing our  price  list  they  will  find  that  the  prices  correspond  to 
those  of  reputable  Eastern  firms;  but  the  saving  lies  in  the 
charge  of  expressage,  which  must  necessarily  be  greater  if  im- 
ported from  a  longer  distance. 

All  that  is  asked  by  this  Company  is  a  fair  trial.  If 
engineers  visiting  San  Francisco  will  take  the  trouble  to  inspect 
the  shop,  we  have  every  reason  to  believe  that  they  can  be  con- 
vinced of  what  we  have  announced. 

We  have  taken  pains  to  add  a  few  testimonials  of  well-known 
men,  from  the  large  number  that  are  on  file.  If  anyone  will 
take  the  trouble  to  peruse  them  he  will  find  all  our  assertions 
fully  endorsed. 

The  Irrigation  Age,  published  in  Chicago,  and  one  of  the 
most  popular  serials  in  the  West,  has  often  referred  to  the  Lietz 
Company  as  one  worthy  of  the  patronage  of  our  professional 
engineers.  With  the  permission  of  that  journal  we  beg  to 
quote  from  its  March  (1893)  number  as  follows: 

The  A.  Lietz  Company  was  organized  in  the  early  part  of  the  year  1892,  having 
been  previously  successfully  engaged  in  the  manufacture  of  scientific  instruments. 
Particular  attention  has  been  given  to  surveying  instruments,  and  it  is  safe  to  say  that 
there  is  not  a  transit,  theodolite  or  level  in  the  market  to-day  that  can  excel  the  articles 
made  by  this  Company.  From  the  time  the  business  was  founded  by  Mr.  Adolph 
Lietz,  some  ten  years  ago,  this  gentleman  was  fully  aware  of  the  rapid  progress  made 
in  the  manufacture  of  surveying  instruments,  and,  alive  to  every  improvement,  skilled 
and  trained  in  his  profession,  he  has  always  been  first  and  foremost  in  adopting  every 


PLATE  V. 
A.  LIETZ  CO.,  SAN  FRANCISCO,  CAL. 


LEVEL  TESTER, 
ADJUSTING  DEPARTMENT. 


APPARATUS  FOR  DETERMINING  THE  MAGNETIC  INFLUENCE  OF  METAL, 
ADJUSTING  DEPARTMENT. 

y 


10  MODERN    SURVEYING    INSTRUMENTS, 

particular  that  could  raise  the  standard  of  the  article.  The  consequence  has  been  the 
production  of  an  instrument  that  seeks  its  equal  anywhere. 

Every  detail  has  had  the  most  careful  consideration.  Of  lenses  and  spirit-levels 
only  the  most  perfect  and  accurate  are  used.  In  the  matter  of  graduations  Mr.  Lietz 
has  made  every  effort  to  achieve  results  that  cannot  possibly  be  excelled  anywhere. 
The  graduating  machine,  built  in  the  establishment,  divides  circles  to  any  required 
refinement,  and  with  a  perfection  in  which  a  wavering  line,  an  unsteady  cut,  or 
an  error  in  division  have  never  been  known.  The  fitting  of  the  centres  is  an  oper- 
ation to  which  a  great  deal  of  time  and  attention  is  given.  It  is  known  that  one 
workman  has  been  exclusively  employed  for  that  particular  part  of  the  work. 

Every  modern  accessory  to  an  instrument  is  made  and  attached.  The  gradienter 
screw,  for  determining  slopes  and  their  degree  by  means  of  divisions  on  a  head  attached 
to  the  tangent-screw  of  the  vertical  movement;  shifting  centers;  variation  plates,  for 
laying  off  the  deviation  of  the  needle;  slide  protectors;  dust  caps  to  leveling  screws; 
verniers  placed  immediately  under  the  eye  of  the  observer;  all  these  are  advantages 
that  the  Lietz  instrument  is  never  without.  The  new  tripod  coupling,  invented  by 
Mr.  Lietz,  has  found  great  favor  with  all  engineers  who  have  used  it.  It  gives  an  in- 
strument rigidity,  and  insures  perfect  safety.  The  attachment  of  the  transit  or  other 
instrument  to  its  tripod  is  made  quickly  by  means  of  three  jaws  that  fit  into  corre- 
sponding grooves.  Testimonials  from  many  of  our  most  capable  engineers  are  con- 
vincing without  further  reference  to  the  matter. 

The  Company  respectfully  requests  that  all  visitors  to  the  Pacific  Coast,  interested 
in  the  articles  manufactured,  call  at  the  shop  on  the  northeast  corner  of  Sansome  and 
Sacramento  streets,  San  Francisco.  Great  pains  will  be  taken  to  show  everybody  what 
the  Pacific  Coast  can  produce  in  this  line  of  delicate  and  beautiful  instruments  of 
precision. 

There  is  the  workshop,  with  its  lathes  and  mechanical  facilities;  the  graduating 
department,  for  the  finer  work  of  the  establishment;  the  adjusting  room,  with  its  col- 
limators  for  the  most  accurate  adjustments  possible;  the  nautical  room,  for  the  repair 
of  compasses  and  sextants;  and  the  foundry,  in  which  the  most  careful  castings  are 
made  for  the  use  in  the  shop. 

This  latter  department  was  added  to  admit  of  aluminium  castings,  of  which  the 
Lietz  Company  has  made  a  specialty.  In  order  to  keep  up  with  the  advancement  of 
the  times  it  was  absolutely  necessary  to  make  provisions  for  building  instruments  of 
that  new  metal,  which  is  beautifully  adapted  for  this  kind  of  work.  They  are  now  in 
the  position  to  manufacture  any  instrument  of  this  material.  Up  to  the  present  time 
the  Company  has  not  placed  aluminium  articles  in  the  market,  but  in  due  time  a  special 
announcement  will  be  made  of  a  new  line  of  goods  that  has  not  seen  its  equal 
anywhere. 

The  Pacific  Coast  is  not  behind  the  times  in  the  building  of  scientific  instruments 
of  precision,  and  we  can  assure  our  readers  that  they  will  find  every  satisfaction  by 
giving  the  A.  Lietz  Company  a  chance  to  do  their  work. 

Eepairs  are  carefully  made  of  all  kinds  of  articles  in  this  line.  The  firm  counts 
among  its  customers  the  best  engineers  of  California,  and  we  can  cheerfully  rec- 
ommend these  gentlemen  to  the  public  as  worthy  of  patronage  and  consideration. 

Irrigation  companies  about  to  Jit  out  for  field  work  will  find  it  to  their  interest  to  con- 
sult with  this  Company  before  sending  East,  where  nothing  better  can  be  purchased,  where 
the  prices  for  high-grade  goods  are  not  any  less,  and  the  freight  considerably  more. 

It  is  quite  needless  to  say  more  in  behalf  of  the  Company 
and  of  the  extent  of  its  work.     It  is  the  patronage  of  our  pro- 


12  THE    A.     LIETZ    COMPANY. 

fessional  engineers  that  we  particularly  desire,  and  their  good- 
will and  confidence  that  we  wish  to  obtain.  For  that  reason 
we  shall  devote  a  large  portion  of  this  catalogue  to  the  descrip- 
tion of  surveying  instruments. 

It  is  to  this  subject  that  we  wish  to  call  your  attention  now; 
and  if  you  will  be  pleased  to  follow  us,  you  will  find  that  we 
have  not  neglected  any  individual  point  in  covering  this  broad 
field.  It  is  our  object  to  show  you  what  we  are  doing  and  how 
we  are  doing  it. 


II. 


DESCRIPTION  OF  INSTRUMENTS 


MANUFACTURED   BY 


THE  A.  LIETZ  COMPANY, 

SAN  FRANCISCO. 

With  Remarks  on   their  proper  Use,  Care,  Preservation 
and  'Adjustments, 


n. 


DESCRIPTION  OF  THE  LIETZ  INSTRUMENTS, 

INCLUDING  REMARKS  ON  THEIR  USE,  HANDLING,  CARE, 
PRESERVATION  AND  ADJUSTMENTS. 


THE  ENGINEER'S  TRANSIT  OR  THEODOLITE. 

In  reviewing  the  different  parts  of  the  transit  and  theodo- 
lite, it  will  answer  our  purpose  to  include  them,  for  the  present, 
under  one  head,  using  both  terms  as  synonymous  —  the  word 
theodolite  having  been  denned  as  an  instrument  of  angular 
measure,  possessing  two  graduated  circles,  normal  to  each  other, 
which  during  manipulation  are  set  in  horizontal  and  vertical 
planes  respectively.  Bauernfeind  says  that  it  is  generally 
believed  that  the  word  theodolite  (theodolith)  is  a  combina- 
tion of  Oia  sight,  odot  road,  and  hO<>$  stone.  He  says  that 
in  order  to  understand  this  derivation  it  must  be  known 
that  formerly  all  supports  upon  which  theodolites  were  placed 
were  made  of  stone.  This  meaning,  however,  seems  somewhat 
ambiguous,  and  other  derivations  have  been  sought.  The  ety- 
mology of  the  word  is  uncertain. 

In  classifying  there  appear  two  distinct  groups  of  theodo- 
lites: the  simple  theodolite  (called  by  us  the  simplified  transit), 
in  which  the  lower  clamp  and  tangential  movement  is  neglected; 
and  the  repeating  theodolite,  possessing  the  double  horizontal 
movement  on  spindle  and  plate,  which  is  the  principal  feature 
of  all  complete  field  instruments  made  for  the  engineer  at  the 
present  time.* 

The  various  parts  of  the  transit  or  theodolite  may  be 
grouped  under  the  following  heads,  viz.: 

Beginning  from  the  base-plate  we  have: 

1 — The    tripod    connection  with    the    leveling,   plumbing 
and  centering  apparatus; 

*  Since  this  was  written,  Mr.  Lietz  has  introduced  his  Cyclotomic  Transit,  which  will 
find  special  treatment  hereafter. 


THE    A.    LIETZ    COMPANY.  15 

2 — The  centers; 

3 — The  graduated  plate  and  verniers; 

4 — The  compass  and  variation  plate; 

5 — The  standards  with  the  vertical  arc  and  its  movements; 

6' — The  gradienter; 

7 — The  spirit  levels; 

8 — The  telescope. 

i.     The  Tripod  Connection. 

An  important  feature  of  all  Lietz  instruments  is  that  the} 
are  attached  to  the  tripod  by  an  entirely  new  device.* 

It  has  been  customary  to  accomplish  this,  heretofore,  in 
two  different  ways.  One  is  to  attach  the  instrument  to  the 
tripod  by  means  of  a  screw  at  the  base-plate,  whereby  it  re- 
mains complete  in  all  its  parts  and  is  never  separated  above  the 
leveling  screws.  This  is  the  method  employed  by  the  best 
makers,  but  it  is  somewhat  tedious  and  unsafe,  as  every  engin- 
eer has  had  occasion  to  find  out.  It  is  often  the  case  that  the 
screw  will  not  catch^  and  there  is  always  a  loss  of  time  and 
patience  in  trying  to  enter  the  thread  properly.  Another  point 
is  that  while  turning  it  on,  the  entire  weight  of  the  instrument 
rests  upon  the  screw  thread,  with  a  constant  tendency  to  wear 
it  away. 

The  second  method  of  fastening  the  transit  to  the  tripod  is 
by  means  of  the  center,  making  it  attachable  or  detachable 
above  the  leveling  screws.  In  most  cases  the  foot  screws  may 
also  be  turned  from  the  tripod  head,  but  it  is  not  unusual  to 
have  them  remain  as  a  fixed  part  of  it.  This  mode  of  coupling 
seems  to  us  very  defective.  The  exposed  center  is  liable  to  in- 
jury in  many  ways.  Dust  particles  accumulate,  and  it  moves 
with  difficulty  in  consequence,  if  it  does  not  cause  fretting. 
But  its  greatest  fault  is  the  incumbent  necessity  of  providing 
for  it  what  is  called  the  flat  center,  for  turning  the  upper  plate. 
In  such  an  instrument  the  plates  stand  too  high  above  the 
leveling  screws,  which  causes  unsteadiness.  We  believe  it 
to  be  very  difficult,  if  not  impossible,  to  do  accurate  work  with 
such  an  instrument,  to  which  point  we  shall  refer  again  here- 
after. 

*  It  has  been  claimed  by  some  that  the  Lietz  Coupling  embraces  the  principles  of  the  old 
Strassburger  Coupling,  and  is  not  new.  We  take  the  opportunity  here  of  correcting  this 
impression.  Any  one  who  will  examine  and  compare  the  two  will  find  the  latter  a  screw- 
coupling^  while  our  design  is  a  friction-coupling,  based  upon  an  entirely  different  principle. 
We  are  not  aware  that  there  is  another  friction -coupling  in  the  United  States  to-day,  and  as 
far  as  we  know,  we  always  have  been  and  are  to  this  day  the  only  manufacturers  of  this 
friction  device  in  the  country. 


16  MODERN    SURVEYING    INSTRUMENTS, 

These  substantial  reasons  have  caused  Mr.  Lietz  to  invent 
a  new  tripod  coupling,  which  is  regarded  as  the  most  successful 
innovation  by  all  who  have  had  occasion  to  use  it. 

The  accompanying  cut  fully  illustrates  this  simple  but  most 
effectual  device. 

On  the  tripod  head,  instead  of  the  ordinary  screw,  there 
are  three  jaws.  The  base  plate  of  the  instrument  is  swallow- 
tail-shaped on  the  inside  (as  shown  at  F)9  and  is  provided  with 
the  spring  case  C.  The  coupling  of  the  two  is  done  by  letting 
one  of  the  grooves  on  the  base  plate  meet  any  one  of  the  jaws  on 
the  tripod  head,  when  one-third  of  a  revolution  to  the  right 
will  make  the  connection;  at  the  same  instant  the  spring  0  will 
fall  into  a  hole  on  the  tripod  head,  which  thus  prevents  any 
possible  disconnection ;  the  latter  is  effected  by  lifting  the  spring 
C  and  turning  to  the  left.  If  the  tripod  head  should  have  been 
worn  or  bent  by  accident,  the  movable  jaw  D,  which  is  worked 
by  the  side-screw  E  (with  a  large  adjusting  pin),  will  again  give 
the  coupling  friction  enough  to  hold  the  instrument  perfectly 
firm  on  the  tripod. 

FIGURE  I. 


The  chief  merit  of  our  arrangement  is  that  it  enables  one 
to  attach  or  detach  the  instrument  to  or  from  its  tripod   more 


THE    A.    LIETZ    COMPANY.  17 

rapidly,  firmly  and  safely  than  by  any  other  device  so  far  known, 
and  that,  too,  without  dividing  the  instrument  proper  into  two 
parts,  which  is  always  injurious  to  its  accuracy  and  stability,  as 
we  have  just  pointed  out.  To  this  we  may  add  that  it  is  more 
durable,  easier  to  keep  clean  and  cannot  get  out  of  repair. 

The  movable  jaw,  once  set  for  the  instrument,  need  not 
again  be  interfered  with.  It  is  absolutely  needless  to  adjust 
the  friction  every  time  the  instrument  is  placed  on  the  tripod. 

We  feel  quite  confident  in  saying  that  every  engineer  who. 
has  once  used  this  new  coupling  will  readily  detect  its  great 
merits,  and  will  never  be  without  it.  All  the  large-sized  trans- 
its and  levels  of  the  Lietz  make  fit  the  same  tripod  head,  and 
are  instantly  adjusted. 

a.     Leveling  Screivs. 

As  these  are  used  more  than  any  other  part  of  the  instru- 
ment, it  is  evident  that  they  should  be  very  durable.  Those  of 
the  Lietz  make  possess  a  very  deep  thread,  rounded  a  little  on 
the  edge,  which  insures  a  very  smooth  motion  and  greater  dur- 
ability than  sharp-edged  threads.  The  screws  are  made  of 
composition  metal. 

The  lower  construction  of  the  transit  is  made  with  the  view 
of  affording  the  greatest  steadiness  under  all  conditions.  For 
that  reason  the  leveling  screws  are  not  run  through  a  thin 
metal  disc,  with  a  common  nut  attached  for  their  operation, 
but  an  extra  strong,  star-shaped  casting,  made  in  one  piece,  is 
provided,  through  which  the  screws  are  passed  and  in  which 
they  operate.  This  "  star  piece  "  A  (see  the  preceding  engrav- 
ing, Figure  I),  is  slotted,  so  that  any  lost  motion  of  the  leveling 
screw  may  be  taken  up  by  the  clamp  screw  B.  This  feature  is 
of  great  importance  in  leveling  instruments  or  transits  used  for 
leveling. 

The  whole  construction  of  this  part  is  intended  to  insure 
the  absolute  steadiness  of  the  instrument,  and  to  give  it  rigid- 
ity even  in  a  strong  wind.  Any  other  construction,  with  a 
light  disc  parallel  to  the  base  plate,  cannot  afford  that  stability 
which  a  first-class  transit  or  level  should  possess;  and,  since 
this  is  one  of  the  prerequisites  of  an  instrument  of  precision, 


18  MODERN    SURVEYING    INSTRUMENTS, 

we  have  laid  particular  stress  upon  our  leveling  arrangement, 
which  is  of  the  most  approved  modern  design. 

The  screws  are  protected  by  dust  caps,  if  desired,  which  is 
a  necessary  addition,  adapted  to  the  climate  of  the  dry  summer 
of  certain  of  our  Coast  localities. 

For  instruments  of  the  greatest  precision,  as  those  used  in. 
triangulatioii  or  geodetic  work,  it  may  be  an  advantage  to  ar- 
range the  base  with  three  leveling  screws  instead  of  four. 
These  changes  will  always  be  made  upon  application.  While 
the  ordinary  complete  transit  is  more  compact  and  of  greater 
utility  with  four  screws,  in  a  specially  designed  instrument  for 
the  finest  work  it  will  always  be  well  to  consider  the  advantages 
of  the  three-screw  system,  universally  adopted  in  European 
instruments. 

b.     Shifting  Center  for  Facilitating  Plumbing  and  Centering. 

All  our  complete  instruments  are  furnished  with  shifting 
plates  for  the  purpose  of  setting  them  precisely  over  a  point, 
after  having  approximately  done  so  by  the  tripod  legs.  This 
arrangement  is  of  the  greatest  utility  to  the  field  man,  and  we 
are  convinced  that  those  who  have  adopted  it  will  never  again 
dispense  with  it. 

While  it  does  not  make  the  instrument  less  rigid  or  port- 
able, it  is  so  easily  manipulated,  and  becomes  a  great  labor- 
saving  factor.  In  order  to  center  the  instrument  accurately, 
two  of  the  leveling  screws  require  a  slight  loosening,  when  the 
transit  may  be  shifted  upon  the  tripod  until  the  center  of  the 
plumb-bob  is  directly  over  the  point  to  be  occupied.  The 
screws  are  then  turned  down  and  the  instrument  leveled  up  in 
the  usual  manner,  when  it  will  stand  as  firm  upon  its  base  as 
required.  We  have  placed  a  thin  metal  plate  under  the  level- 
ing screws, intended  to  prevent  the  accumulation  of  dust  between 
the  two  shifting  plates. 

2.     The  Centers. 

In  manufacturing  this  all-important  feature,  the  very  back- 
bone of  the  instrument,  too  much  care  and  attention  cannot  be 
bestowed. 


THE    A.    LIETZ    COMPANY.  }g 

It  is  essential  that  both  of  these  metal  axes  should  have  the 
same  absolute  center  as  the  graduated  plate  and  the  horizontal 
telescope  axis,  whichever  way  the  instrument  may  be  turned. 
This  is  accomplished  by  the  A.  Lietz  Company  by  making  this 
detail  a  specialty.  The  carefully  chosen  material  for  the  ver- 
tical axes,  the  exact  method  of  turning  and  fitting  them,  and 
the  precision  reached  in  the  manner  of  centering  them,  to- 
gether with  the  subsequent  scrutinizing  test  to  determine  the 
slightest  eccentricity,  have  accomplished  results  as  perfect  as 
mechanical  means  and  human  ingenuity  can  achieve. 

Eccentricity  has  been  a  source  of  annoyance  and  error  to 
the  engineer,  to  determine  which  a  number  of  practical  meth- 
ods have  been  invented  and  put  to  use.  One  of  the  most  in- 
genious has  been  inserted  in  this  catalogue,  which  will  be  found 
in  full  elsewhere. 

But  with  our  modern  transit,  if  used  with  ordinary  care,  • 
this  source  of  error  has  been  eliminated,  or  at  least  reduced  to 
the  lowest  possible  minimum. 

The  length  of  our  centers  is  from  2J  to  4  inches,  according 
to  size  and  style  of  instrument.  To  our  best  belief,  this  is 
more  than  the  instruments  of  any  of  the  many  different  mak- 
ers possess,  having  constantly  handled  a  great  many  of  them  in 
repairing.  Yet,  by  examining  our  illustrations,  it  will  be  no- 
ticed that  with  us  the  limb  and  vernier  plates  are  nearer  to  the 
tripod  head  than  in  those  of  other  make,  owing  to  the  judicious 
placing  of  the  centers,  which  reach  down  into  the  base,  thus 
insuring  the  utmost  stability.  By  comparing  our  cuts  with 
those  in  other  catalogues,  the  reader  will  obtain  a  pretty  fair 
idea  of  what  we  mean  to  impress  upon  him — such  a  comparison 
being  better  than  any  argument  by  either  ourselves  or  others 
based  upon  mere  assertion. 

Examine  carefully  our  construction  of  the  centers,  and 
you  will  be  soon  convinced  that  our  claim  for  rigidity  and  sta- 
bility is  fully  warranted. 

3.     The  Graduated  Plate. 

We  have  now  come  to  the  most  essential  part  —  the  very 
soul  of  the  instrument.  It  is  needless  to  dwell  upon  the  neces- 


20  MODERN    SURVEYING    INSTRUMENTS, 

sity  of  an  accurate  graduation;  it  is  self-evident,  and  it  becomes 
the  instrument-maker's  pride  to  make  it  so. 

We  guarantee  our  work  in  this  particular  as  perfectly  reli- 
able, the  graduation  lines  straight,  thoroughly  black  and  of 
uniform  width. 

The  plate  is  accurately  centered  and  free  from  eccentricity, 
as  already  explained. 

The  horizontal  circle  is  graduated  from  0  to  360  degrees, 
with  two  sets  of  figures  running  in  opposite  directions  (unless 
ordered  differently).  They  are  large  and  distinct,  and,  to 
avoid  errors  in  reading,  the  figures  of  these  two  sets,  and  those 
on  their  corresponding  verniers,  are  inclined  on  opposing  slants, 
thus  indicating  the  direction  in  which  the  vernier  should  be 
read. 

We  recommend  graduations  on  a  solid  silver  ring,  as  that 
metal  offers  many  advantages  for  the  purpose — in  fact,  its  great 
permanency  and  smoothness  renders  it  the  only  satisfactory 
surface  for  fine  graduations.  However,  they  are  made  as  the 
customer  desires;  but  since  the  additional  outlay  for  silver 
graduation  is  only  $10,  we  seldom  have  any  difficulty  in  im- 
pressing the  purchaser  with  its  advantages. 

It  is  customary  with  us  to  graduate  circles  so  that  they  may 
be  read  to  thirty  seconds  or  twenty  seconds  of  arc.  We  make  any 
degree  of  refinement  called  for,  but  our  manufactured  goods  are 
always  on  hand  in  the  two  vernier  divisions  named. 

a.     The  Vernier. 

This  consists  of  a  small  sliding  scale,  movable  upon  a 
larger  one,  so  graduated  that  n  parts  thereof  shall  include  either 
7i-)-l,  orTi —  1  parts  of  the  larger  scale.  The  scale  "may  be 
applied  to  either  straight  lines  or  arcs,  and  aids  to  determine 
the  smaller  divisions  of  measure  between  the  lines  on  the 
larger  scale. 

A  tedious  method  for  measuring  small  values  of  arc  by 
means  of  concentric  circles  was  given  in  the  early  part  of  the 
sixteenth  century  by  a  Portuguese,  Pero  Nunez  (Nonius),  and 
after  him  the  name  of  nonius  is  still  applied  in  Germany  and 
other  countries  to  what  we  exclusively  call  a  vernier  here. 


THE    A.     LIP:TZ    COMPANY.  21 

This  term  was  justly  given  it  in  honor  of  the  Dutch  captain, 
Peter  Werner,  who  gave  to  the  scale  the  sliding  shape  in  which 
we  now  apply  and  use  it  practically.  Signing  himself  "  Pierre 
Vernier"  in  a  discussion  of  the  "Nonius,"  written  by  the  in- 
ventor in  the  French  language  and  published  in  Brussels  in 
1631,  gave  rise  to  the  term  we  now  almost  universally  employ. 
The  graduations  on  a  vernier  are  usually  so  made  that  n 
divisions  thereof  shall  equal  n  —  1  divisions  on  the  circle. 

It  becomes  a  simple  problem  to  determine  the  value  of  n 
from  the  following  equation: 

Let  I  =  length  of  one  division  on  circle, 

li=  length  of  a  vernier  division,  it  is  evident  that 
I  (n—1)  =  li  n  ,  or 
I 


l—LL' 

The  value  of  any  quantity  in  the  equation  may  then  be 
readily  expressed  in  terms  of  the  other;  I  —  h,  or  the  smallest 

readable  division,  being  equal  to  — . 

n 

It  is  customary  to  graduate  the  circles  of  the  Lietz  transits 
in  20-minute  divisions,  reading  to  either  20  or  30  seconds  on 

20  X  60 
the  vernier.      The  value  of  n  in  these  cases  is  -          — ,  or  60  in 

20 

the  former,  and  -   — ,  or  40  in  the  latter;  or,  in  other  words, 

oO 

59  and  39  divisions  on  the  circle  will  correspond  to  60  and  40 
on  the  vernier  respectively.  Instruments  reading  to  one  min- 
ute of  arc  are  divided  to  30  minutes  on  the  plate;  in  that  case 

29  circle  spaces  are  equal  to  30  vernier  spaces. 

Every  good  instrument  should  have  two  verniers;  they 
should  be  covered  with  glass  to  protect  them  from  exposure, 
and  for  ease  in  reading  they  should  be  provided  with  ground 
glass  shades. 

Our  verniers  are  in  such  position  that  the  observer  need 
not  step  aside  in  order  to  read  them,  for  we  place  them  about 

30  degrees  from  the  line  of  collimation.     The  method  of  thus 
placing  them  has  been  pronounced  objectionable,  because  the 
size  of  the  plate  level,  which  is  at  right-angles  to  the  line  of 
collimation,  and  the  more  important  of  the  two,  has  to  be  re- 


22  MODERN    SURVEYING    INSTRUMENTS, 

duced.  By  examining  our  instruments,  however,  anyone  will 
see  that  we  have  attained  the  object  without  reducing  its  length, 
without  placing  it  over  the  vernier,  and  without  allowing  it  to 
extend  beyond  the  circumference  of  the  plate  —  all  of  which 
would  be  very  objectionable  features,  indeed. 

The  space  between  the  circle  and  the  vernier  must  appear, 
through  a  magnifying  glass,  like  a  fine  black  line.  No  accurate 
reading  can  be  taken  if  the  space  appears  wider  than  a  mere 
line  of  uniform  thickness  under  the  revolution  of  the  plate. 

6.     Clamp  and  Tangent  Screws. 

The  lower  clamp  screw  of  our  transit  is  of  the  best  devised 
shape  and  arrangement.  It  is  strong  and  rigid,  and  answers 
the  slightest  touch. 

The  upper  clamp  does  not  come  in  contact  with  the  limb, 
but  grasps  the  sleeve  of  the  outside  center.  This  is  far  prefer- 
able to  the  old  method  of  pressing  together  the  two  plates  by 
means  of  a  screw  placed  at  some  point  on  the  circumference. 

The  tangent  screws  are  single  only,  and  operate  in  metal 
cases  against  opposing  springs.  Great  care  has  been  bestowed 
in  eliminating  all  lost  motion  of  these  screws.  We  consider 
double  tangent  screws,  working  against  a  tongue,  as  entirely 
obsolete.  Any  instrument  sold  to-day  with  double  opposing 
tangent  screws  may  be  set  down  as  antiquated  and  behind  the 
times.  It  is  absolutely  necessary  that  everything  tending  to 
create  lost  motion  must  be  carefully  avoided.  While  adjusting 
the  line  of  collimation,  this  source  of  error  becomes  very 
annoying,  for,  in  revolving  the  telescope,  the  plate  is  liable  to 
turn  slightly  and  the  operator  is  never  sure  whether  the  cross- 
hairs are  in  adjustment  or  not. 

The  arrangement  of  our  tangent  screws  combine  simplicity 
with  absolute  reliability.  Being  single,  they  require  but  one 
hand  in  manipulation,  and  their  judicious  location  and  spring 
case  arrangement  make  them  active  and  operative  at  any 
instant. 

4.     The  Compass. 

Our  needle  differs  somewhat  in  shape  from  others,  being  a 
little  smaller  in  the  center  than  towards  the  ends,  for  the  reason 


THE    A.     LIETZ    COMPANY.  23 

that  the  magnetic  influence  is  manifested  at  the  ends  only,  so 
that  all  the  central  metal  may  be  called  dead  weight.  Compared 
with  those  of  other  makers,  the  Lietz  needle  is,  therefore,  a 
little  lighter,  which  conditions  the  increased  durability  of  the 
point  upon  which  it  poises. 

Hard  steel  has  the  capacity  of  retaining  magnetism  longer 
and  better  than  when  tempered,  and  for  that  reason  we  have 
adopted  the  plan  of  leaving  one-half  inch  on  both  ends  per- 
fectly hard. 

The  closest  attention  is  given  to  the  center  cap  —  which 
contains  an  agate  setting — and  to  the  pin  upon  which  the  needle 
rests,  for  the  accuracy  or  sensitiveness  depends  principally  upon 
these  two  details.  These  needles  possess  that  degree  of  sensi- 
tiveness required  in  a  high-grade  instrument.  A  sluggish 
needle — one  that  will  hang  like  a  dead  load  —  is  not  fit  for  the 
observation  of  a  reliable  azimuth. 

The  center  pin  must  occupy  the  true  center  of  the  gradu- 
ated circle,  and  must  stand  normal  to  its  plane.  We  utilize 
precise  instruments  with  high  magnifying  power  to  obtain  the 
absolute  true  position  of  the  pin,  in  order  to  avoid  all  errors 
due  to  eccentricity. 

The  lifting  arrangement  is  applied  with  the  view  of  raising 
and  lowering  the  needle  gently  and  gradually,  as  any  sudden 
drop  to  the  pin,  or  any  quick  action  of  arresting  its  motion,  is 
sure  to  cause  a  rapid  wearing  of  the  point  and  the  cap. 

The  Compass  is  divided  into  30-minute  divisions,  and  num- 
bered from  0  to  90  degrees  in  each  quadrant  from  the  north 
and  south  points.  This  is  done  to  conform  with  the  usual 
practice  of  surveyors  in  this  country  to  record  bearings  in  the 
four  quadrants.  But  any  desired  method  of  numbering  the 
compass,  either  from  0  to  180  degrees,  or  from  0  to  360  degrees, 
may  be  had  upon  application. 

In  order  to  record  at  once  the  true  bearings  in  the  field, 
instead  of  the  magnetic,  the  complete  instrument  is  provided 
with  a  variation  plate,  i.e.,  an  arrangement  for  laying  off  the 
local  deviation  of  the  needle  by  a  movement  of  the  graduated 
compass  ring,  so  that  the  indicated  course  of  a  line  shall  show 
at  once  its  relation  to  the  true  meridian.  It  is  so  made  that 


24  MODERN    SURVEYING    INSTRUMENTS, 

the  variation  may  be  laid  off  with  precision  to  the  minute,  by  the  aid  of 
the  instrument's  vernier. 

This  is  done  in  the  following  manner: 

Having  set  the  plate  vernier  to  zero,  adjust  the  instrument 
and,  with  the  aid  of  a  good  reading  glass,  place  it  in  such  a 
direction  that  the  north  end  of  the  needle  shall  point  to  the 
zero  of  the  compass  ring,  which  latter  must  coincide  with  the 
little  pointer  provided  for  that  purpose.  Having  carefully  set 
the  instrument  thusly  by  means  of  the  lower  clamp  and  its 
tangent  screw,  which  can  certainly  be  done  to  the  nearest 
minute  of  arc,  we  release  the  clamp  of  the  plate  and  proceed  to 
lay  off  the  amount  of  the  local  deviation  of  the  needle  in  de- 
grees and  minutes  by  means  of  the  plate-vernier  —  to  the  left 
if  the  variation  be  east.  The  instrument  is  now  again  in  a 
fixed  position,  the  telescope  pointing  to  the  true  north,  or  as 
much  to  the  left  of  the  needle  as  the  magnetic  variation  is  east. 
We  now  detach  the  little  screw  on  the  side  of  the  compass  ring, 
and  proceed  to  turn  the  ring  until  its  zero  shall  coincide  exactly 
with  the  north  end  of  the  needle,  when  every  subsequent  read- 
ing of  the  compass,  in  any  position,  will  indicate  the  bearing 
of  the  vertical  telescope  axis  from  the  true  meridian. 

This  simple  little  device  is  fully  up  to  the  standard  of  ac- 
curacy required,  for  with  care  in  setting  the  needle  we  can 
always  obtain  results  correct  within  the  nearest  minute.  We 
find  that  by  this  method  the  additional  vernier,  usually  placed 
inside  of  the  compass  ring,  becomes  superfluous,  as  the  plate 
and  vernier  of  the  transit  are  perfectly  capable  of  taking  care 
of  the  duties  of  this  unnecessary  accessory. 

The  variation  plate  has  proven  a  great  labor-saving  device, 
as  the  observed  courses  require  no  reduction  to  the  true  merid- 
ian subsequently.  It  is  now  almost  universally  called  for;  and 
for  those  practicioners  with  whom  land  surveying  is  a  specialty 
we  should,  by  all  means,  recommend  it  as  an  indispensible 
feature.  No  complete  instrument  is  without  it. 

5.     The  Standards  and  Vertical  Arc. 

The  standards  are  so  constructed  as  to  give  the  maximum 
support  to  the  telescope,  commensurate  with  the  size  of  the 
plate.  They  are  light,  but  rigid  and  strong. 


THE    A.     LIETZ    COMPANY.  25 

To  avoid  unequal  expansion  of  the  metal  in  the  standards 
by  exposure  in  the  hot  sun,  which  has  a  tendency  to  elevate 
one  end  of  the  telescope  axis  and  to  depress  the  other,  vitiating 
the  adjustment,  they  are  now  what  is  called  cloth-finished. 
This  finish,  being  a  non-conductor  of  heat,  reduces  to  a  mini- 
mum this  source  of  possible  error,  which,  in  very  sensitive 
instruments,  is  of  sufficient  moment  to  be  guarded  against. 
Other  parts  of  our  instruments  are  also  finished  in  the  same 
manner,  particularly  level  telescopes,  which  we  shall  have 
reason  to  mention  again  hereafter. 

The  bearings  for  the  telescope  axis  are  made  with  extra 
care  and  attention. 

The  axes  of  the  Lietz  transit  telescopes  are  cut  to  conical 
bearings,  which  is  a  feature  altogether  preferable  to  the  cor- 
rugated shape  frequently  found  in  surveying  instruments. 
The  advantage  of  the  former  is  very  evident,  in  that  there  is 
less  friction  than  by  any  other  contact;  and,  in  addition  to 
that,  it  affords  a  much  finer  fitting  by  reason  of  its  conical 
shape.  But  it  is  very  essential  that  the  hardest  metal  should  be 
used  for  this  purpose,  as  a  material  of  insufficient  hardness 
would  soon  wear,  and  the  axes  would  become  elliptical. 

One  of  the  standards  is  supplied  with  an  adjusting  screw, 
to  regulate  any  inaccuracy  in  the  motion,  of  the  telescope  in 
the  true  vertical  plane,  when  the  centers  of  the  instrument 
stand  vertically. 

One  standard  carries  the  arc  for  observing  vertical  angles, 
which  may  be  either  a  full  or  a  half-circle,  as  the  customer  de- 
sires. It  is  usually  made  to  read  to  minutes,  but  may  be  grad- 
uated finer  if  so  ordered.  A  clamp  and  tangent  screw  are 
provided  on  the  right-hand  standard,  which  are  made  like  those 
already  described  for  the  horizontal  movement.  Every  part  of 
the  vertical  measuring  apparatus  is  strongly  and  accurately 
made  and  fitted,  to  insure  the  best  results  in  its  practical  appli- 
cation. 

6.     The  Gradienter. 

The  head  of  the  tangent  screw  of  the  vertical  arc  move- 
ment is  made  somewhat  larger,  properly  silvered  and  graduated 
into  a  number  of  equal  parts  on  its  circumference,  the  thread 


26  MODERN    SURVEYING    INSTRUMENTS, 

of  the  screw  being  cut  with  grea,t  precision,  so  that  its  revolu- 
tion may  be  accurately  recorded  by  the  divisions  of  the 
micrometer  head. 

One  complete  revolution  of  the  screw  corresponds  to  -/-g-  of 
a  foot  of  difference  in  level  in  100  feet.  Since  the  head  is  di- 
vided into  fifty  parts,  it  follows  that  one  division  equals  a  dif- 
ference of  y^-g-  of  a  foot  in  100  feet. 

With  this  attachment  grades  may  be  established  very 
quickly.  It  is  only  necessary  to  set  the  screw  head  to  zero, 
level  and  clamp  the  telescope,  and  turn  the  screw  up  or  down 
as  many  spaces  as  there  are  hundredths  of  a  foot  of  rise  or  fall 
in  one  hundred  feet  of  the  grade  to  be  laid  out.  With  the 
small  scale  over  the  screw  thrown  back,  the  gradienter  is  used 
as  an  ordinary  tangent  screw.  It  is  one  of  the  most  useful  ac- 
cessories, is  easily  applied,  and  adds  nothing  to  the  weight  of 
the  instrument. 

This  attachment  is  also  useful  in  the  determination  of  hor- 
izontal distances,  it  being  obvious  that  the  difference  in  rod 
reading  between  two  complete  revolutions  of  the  screw  will  in- 
dicate at  once  the  distance  of  the  rod  from  the  observer.  Where 
the  ground  is  level,  or  nearly  so,  the  simple  difference  in  rod 
reading  will  suffice;  but  when  this  is  not  the  case,  the  necessary 
corrections  will  have  to  be  applied  to  obtain  the  true  horizontal 
distance. 

7.     The  Spirit  Levels. 

We  have  already  noted  that  for  our  purposes  we  import  the 
very  best  article  obtainable  in  Europe. 

An  instrument  of  precision,  capable  of  measuring  delicate 
differences,  requires  delicate  and  sensitive  levels.  This  is  so 
obvious  that  we  ought  not  to  call  attention  to  it  here,  were  it 
not  for  the  fact  that  we  are  frequently  approached  by  surveyors 
who  wish  to  impress  upon  us  the  idea  that  this  or  that  make  of 
instrument  met  with  their  approval  because  its  bubbles  would 
stay  in  place  when  once  adjusted.  For  this  reason  we  want  to 
repeat  that  it  is  no  claim  for  superiority  of  a  spirit  level  because 
it  works  sluggishly.  An  engineer  in  the  field  must  know  when 
his  instrument  is  absolutely  level,  and  its  bubbles  should  indi- 
cate to  him  at  once  when  this  is  not  the  case.  If  they  do  not 


THE    A.     LIETZ    COMPANY.  27 

do  so,  then  the  instrument  does  not  come  up  to  the  required 
standard  of  a  precise  tool.  It  would  hardly  do  to  place  a  car- 
penter's level  on  a  transit,  yet  we  have  110  doubt  that  its  excel- 
lent qualities  of  remaining  stationary  would  find  admirers. 

Remember,  also,  that  sluggish  levels  are  cheaper,  and  that 
it  is  not  to  the  instrument-maker's  financial  benefit  to  put  in  a 
delicate  and,  therefore,  much  more  costly  article. 

There  is,  of  course,  a  limit  to  the  degree  of  sensitiveness, 
and  that  we  never  exceed,  adapting  it  in  all  cases  to  the  work 
demanded  of  the  particular  instrument  in  hand. 

Our  levels  are  ground  to  the  proper  curvature,  and  each  is 
carefully  tested  upon  our  level  tester  before  it  is  attached  any- 
where. 

8.     The  Telescope. 

We  have  now  reached  another  most  essential  feature  of  the 
instrument — that  which  may  be  compared  to  the  head  of  the 
body,  containing  the  delicate  organ  of  sight  —  the  lens. 

a.      The  Lenses. 

We  have  already  called  attention  to  the  fact  that  our  optical 
accessories  are  imported  from  Europe,  and  that  we  take  great 
pains  to  obtain  the  best  article  for  the  purpose. 

Without  going  into  the  detail  of  optical  mathematics  and 
formulae,  that  can  be  readily  found  in  any  text-book  on  physics, 
we  all  know  that  it  has  been  the  constant  aim  to  produce  lenses 
as  free  from  spherical  and  chromatic  aberration  as  it  is  possible 
to  make  them.  The  lenses  of  the  Lietz  telescopes  are  of  the 
now  celebrated  Jena  glass — an  achievement  in  theoretical  and 
practical  science  that  ten  years  ago  was  unknown,  and  of  which 
it  would  be  interesting  to  make  some  explanation  here. 

THE  JENA  GLASS  WORKS. 

The  far-famed  glass  melting  works  for  optical  and  scientific 
purposes  of  Schott  and  Associates,  in  Jena,  was  founded  in  1884 
by  men  who  were  of  eminent  scientific  attainments,  and  who 
based  the  magnificent  industry  upon  long  continued  research 
in  this  particular  field.  Our  information  comes  from  a  short 
description  furnished  by  the  leading  men  of  the  enterprise, 


28  MODERN    SURVEYING    INSTRUMENTS, 

which  was  published  some  time  ago  in  connection  with  a  list  of 
the  glass  varieties  manufactured. 

The  industry  originated  from  a  series  of  scientific  investi- 
gations made  for  the  purpose  of  determining,  from  their  chem- 
ical combinations,  the  resulting  optical  properties  of  fusible 
compositions  having  an  amorphous  congelation.  These  exper- 
iments were  undertaken  by  Professor  Abbe  and  Dr.  Schott,  to 
obtain  information  regarding  the  chemical  and  physical  prin- 
ciples underlying  the  manufacture  of  optical  glass.  This  work 
began  in  January,  1881,  and  was  prosecuted  in  accordance  with 
a  pre-arranged  plan  in  such  wise:  that  Dr.  Schott  made  the 
necessary  melting  tests  at  his  home  in  Witten,  while  the  optical 
investigations  of  the  samples  obtained  were  carried  on  in  Jena 
by  Professor  Abbe,  or  his  assistant,  Dr.  Kiedel,  by  means  of 
spectroscopic  analysis. 

The  melting  tests  were  made  at  that  time  on  a  very  small 
scale  (not  over  300  to  900  grains  in  bulk),  and  were  solely  di- 
rected to  the  one  object  of  studying  carefully  the  influences  of 
all  chemical  elements  that  may  possibly  obtain  in  any  form  in 
amorphous  fusible  compositions,,  upon  the  power  of  refraction 
and  dispersion  in  their  manifold  combinations. 

By  carefully  continuing  the  investigations  in  this  manner 
to  the  end  of  the  year  1881,  a  number  of  facts  and  data  had 
been  collected  regarding  the  specific  optical  effect  of  certain 
masses,  which  gave  promises  of  new  glass  combinations  that, 
for  certain  purposes,  would  possess  more  advantageous  charac- 
teristics than  those  offered  by  the  ordinary  crown  and  flint. 

In  order  to  utilize  these  results  in  practical  optics  as  much 
as  possible,  it  was  decided  to  continue  the  work  on  a  new  plan, 
and  that  was:  to  combine  systematically  glass  fusions  on  the 
optic-chemical  principles  established  by  the  preceding  experi- 
ments that  should  possess,  as  far  as  possible,  all  the  desirable 
optical  properties,  together  with  other  physical  qualities  fitting 
them  specially  for  practical  use,  such  as  hardness,  unchange- 
ableness,  freedom  for  color,  etc. 

With  this  end  in  view,  Dr.  Schott  removed  his  residence 
to  Jena  in  the  spring  of  1882,  where  a  special  laboratory,  with 
every  facility  for  melting,  was  fitted  up  in  a  building  rented  for 
the  purpose. 


THE    A.    LIKTZ    COMPANY.  29 

With  the  aid  of  gas  furnaces  and  modern  blowing  appara- 
tus, it  became  possible  to  make  melting  tests  on  an  amply  large 
scale,  up  to  quantities  of  about  25  pounds. 

With  the  assistance  of  another  chemist  for  the  analytical 
investigations,  which  had  to  be  carried  on  simultaneously  with 
the  synthetical  work,  and  one  workman,  the  tests  were  contin- 
ued in  this  laboratory  until  the  end  of  the  year  1883,  whereby 
two  special  lines  of  investigation  were  closely  followed,  which 
practical  optics  had  laid  out  as  the  principal  directions  of  re- 
search. 

The  first  problem  considered  the  making  of  crown  and  flint 
glass  couples,  possessing  as  near  as  possible  a  proportional  dis- 
persion.in  the  various  sections  of  the  spectrum,  for  the  purpose 
of  obtaining  a  higher  degree  of  achromatism  than  had  hereto- 
fore been  possible  by  employing  the  usual  optical  glass;  that  is, 
it  was  sought  to  obviate,  or  to  reduce  the  very  considerable  sec- 
ondary aberration,  which  the  silicate  glasses  still  permit  in  all 
their  achromatic  combinations,  and  which  is  due  to  the  dispro- 
portionate dispersive  powers  in  crown  and  flint. 

The  second  problem  —  considered  of  no  less  importance, 
although  the  subject  involved  had,  generally  speaking,  not  been 
deemed  a  necessary  feature  in  optics  up  to  that  time  —  consisted 
in  obtaining  a  greater  variety  of  gradations  or  modifications  of 
the  two  principal  constants  in  optical  glasses,  viz.:  the  expo- 
nent of  refraction  and  the  mean  dispersion. 

The  silicate  glasses  in  use  at  that  time,  true  to  the  simplicity 
and  uniformity  of  their  chemical  constituents,  show  images  of 
a  simple  series  in  which,  ascending  from  the  lightest  crown  to 
the  heaviest  flint,  the  dispersion  increases  in  the  same  measure 
as  the  exponent  of  refraction  increases,  up  to  very  small  and 
practically  immaterial  deviations. 

.  But  the  theoretical  consideration  of  dioptric  questions 
establishes  without  doubt,  that  it  would  simplify  greatly  this 
problem,  in  which  numerous  conditions  are  to  be  fulfilled  at 
the  same  time,  if  the  optician  had  his  choice  of  such  glasses,  in 
which  the  dispersion  with  the  same  index  of  refraction,  or  the 
index  of  refraction  with  a  constant  dispersion,  could  be  made 
to  undergo  a  very  considerable  gradation.  In  this  direction  it 


30  MODERN    SURVEYING    INSTRUMENTS. 

must  be  looked  upon  as  a  progressive  step,  that  the  systematic 
use  of  a  greater  number  of  chemical  elements  in  glass  fusions 
makes  it  possible  to  create  the  varying  grades  referred  to — that 
is,  it  enables  one  to  extend  the  variety  of  glasses  at  disposal,  in 
some  places  at  least,  in  two  dimensions,  which  heretofore  had 
been  essentially  linear  in  character;  but  the  realization  of  this 
advance  in  practice  may  only  be  expected  gradually,  because  of 
the  necessity  of  supplying  further  theoretical  and  mathematical 
bases  for  these  productions. 

The  experiments  led  to  the  most  satisfactory  results,  which, 
for  the  purpose  of  our  catalogue,  it  would  be  unimportant  to 
elaborate  in  further  detail;  suffice  it  to  say  that  the  faithful 
endeavors  of  these  men  were  universally  appreciated,  and  that 
their  conclusions  gained  the  fullest  confidence  of  those  who 
were  best  able  to  judge  of  the  value  of  their  labors. 

The  results  were  reached  in  the  autumn  of  1883,  and  the 
entire  research  would  have  been  completed  then,  had  it  not 
been  for  the  instigation  on  the  part  of  several  prominent 
scientists,  that  the  investigators  take'  hold  of  the  practical  ap- 
plication of  their  theoretical  achievements  themselves,  and  to 
begin  the  industrial  production  of  this  article  immediately  in 
connection  with  the  preceding  laboratory  research. 

This  finally  led  to  the  erection  of  glass  melting  works  at 
Jena,  with  all  the  facilities  for  successful  practical  operation, 
established  with  the  cooperation  of  Doctors  Carl  and  Rod.  Zeiss, 
who  had  previously  given  valuable  assistance  in  the  preliminary 
investigations.  In  the  autumn  of  1884  the  factory  was  in  con- 
dition to  prepare  for  the  production  of  optic  glass  on  a  large 
scale — both  of  the  kind  previously  in  use,  as  well  as  that  of  the 
newly  created  combinations.  -* 

To  carry  out  the  necessary  and  very  expensive  experiments 
on  a  factory  scale,  it  was  fortunate  that  means  were  furnished 
by  a  number  of  liberal  appropriations  granted  from  the  Prussian 
State  Treasury,  which  received  the  hearty  endorsement  of  all 
scientific  circles. 

After  surmounting  great  and  numerous  difficulties,  natur- 
ally retarding  the  progress  in  a  new  technical  field,  in  which  the 
enterprise  is  thrown  entirely  upon  its  own  resources,  without 


THE    A.    LIETZ    COMPANY.  31 

any  assistance  from  previous  experience,  the  Jena  factory  has 
now  become  a  successful  industry  that  has  made  its  way  to  re- 
main as  a  valuable  permanent  feature.  Its  capabilities  have 
been  sufficiently  tested  during  the  last  eight  years,  in  the  inter- 
course with  most  of  the  optical  works  in  Europe,  so  that  it  is 
now  fully  able  to  compete  with  them  on  a  commercial  basis. 

These  remarks  on  the  Jena  glass  factory  will  convince  the 
reader  that  the  article  deserves  that  general  preference  which 
is  universally  given  it  —  its  evolution  is  one  based  upon  a  true 
scientific  foundation  —  for,  in  this  case,  the  practical  appli- 
cation depended  entirely  upon  a  previous  theoretical  research, 
and  theory  and  practice  must  work  hand  in  hand  to  achieve 
lasting  results.  A  new  era  in  optics  began  when  the  Jena 
glass  became  a  merchantable  article.  And  this  new  optical  ad- 
vance was  not  without  effect  upon  those  fields  of  science  in 
which  optical  apparatus  is  used,  for  the  achievements  in  one 
particular  line  alone  —  in  microscopy  —  received  a  fresh  impulse 
from  that  time,  which  was  again  felt  in  other  departments,  as 
in  physiology,  biology,  bacteriology,  hygiene  —  those  most  im- 
portant to  the  welfare  of  man. 

This  short  diversion  leads  us  again  to  the  subject  of  the 
telescope  for  engineering  purposes,  with  which  we  are  more 
particularly  concerned. 

b.     The  Object  Glass. 

Arrangements  have  been  made  by  which  our  lenses  are 
specially  ground  for  us  in  Europe,  and  not  one  is  accepted  that 
will  not  stand  the  most  critical  test.  We  receive  objectives 
and  eye-pieces  in  sets  at  stated  periods,  so  that  we  are  always 
in  position  to  supply  our  demand.  Neither  time,  trouble  nor 
expense  has  been  spared  to  produce  a  telescope  up  to  the  stand- 
ard of  the  most  approved  pattern,  that  shall  possess  all  the 
refinement  required  of  an  instrument  designed  for  scientific 
work. 

The  objective  is  formed  by  a  combination  of  two  lenses,  a 
crown  and  a  flint  glass,  one  of  which  is  bi-convex,  the  other 
plano-concave.  The  inner  faces  have  the  same  curvature. 
As  the  concave  lens  has  the  longer  focal  length,  this  combi- 
nation maintains  the  characteristics  of  one  convex  lens.  The 


32  MODERN    SURVEYING    INSTRUMENTS. 

focal  lengths  are  so  proportioned  that  the  dispersion  caused  by 
the  crown-glass  lens  is  corrected  by  the  flint  —  the  well-known 
principle  of  counteracting  the  dispersion  of  light  of  one  lens  by 
interposing  another  of  a  different  glass  is  made  use  of. 

Our  objectives  possess  these  achromatic  lenses,  made  of  the 
Jena  glass,  with  special  care,  by  the  most  skilful  opticians.  The 
focal  lengths  of  these  objectives  vary  from  17J  inches,  in  the 
case  of  the  large  Y-level,  to  10  inches,  in  the  large  transit, 
and  to  7J  inches  in  the  smaller  instrument. 

In  mounting  the  two  lenses  in  the  cell,  great  care  is  taken 
that  their  axes  are  made  to  coincide.  Should  this  important 
point  be  neglected,  an  indistinctness  of  image  would  be  likely 
to  result. 

c.     The  Eye-Piece. 

The  simplest  form  is  the  so-called  Kamsden  eye-piece,  in 
which  two  plano-convex  lenses  are  mounted  so  as  to  turn  the 
convex  surfaces  towards  each  other.  The  distance  between 
them  is  such  that  the  chromatic  aberration  of  one  lens  is  cor- 
rected by  the  other  —  which,  however,  is  not  fully  accomplished. 

Another  form  of  eye-piece  was  invented  by  the  optician 
Karl  Kellner,  of  Wetzlar,  and  fully  described  in  a  paper  pub- 
lished in  1849.  It  was  called  the  orthoscopic  ocular  (from  opOo? 
straight,  and  ff/.oxsa>  observe),  by  reason  of  its  principal  ad- 
vantageous feature  of  furnishing  of  every  object  a  straight, 
perspectively  correct,  and,  in  every  extent,  sharp  and  weil  de- 
fined image.  The  Kellner  eye-piece  also  consists  of  two  lenses: 
a  biconvex  collective,  of  which  the  flatter  curvature  is  turned 
towards  the  objective,  and  an  achromatic  eye-glass,  whose  con- 
struction is  similar  to  the  Fraunhofer  achromatic  lens. 
According  to  the  inventor's  description,  the  three  lenses  used 
in  this  eye-piece  possess  only  four  reflecting  surfaces,  and  the 
two  lenses  composing  the  eye-glass  must  therefore  come  in  ab- 
solute contact  with  each  other.  There  may  be  two  forms  of  the 
eye-lens:  a  plano-convex,  with  the  curved  face  towards  the 
collective;  and  the  doubly-convex. 

An  ocular  of  this  order,  wherein  both  the  collective  and 
the  eye-lens  are  compound,  is  the  Steinheil  eye-piece,  which  is 
doubly  achromatic,  but  which  gives  a  very  flat  field. 


THE    A.    LIETZ    COMPANY.  33 

These  forms  of  positive  eye-pieces,  wherein  the  focus  of  the 
objective  lies  in  front  of  the  combination,  together  with  several 
of  the  negative  form  (the  Huyghens  and  the  Airy),  wherein  the 
objective's  focus  lies  between  the  two  lenses,  give  an  inverted 
image,  which  is  considered  by  many  as  an  undesirable  feature 
in  surveying  instruments.  Nevertheless,  they  possess  many 
valuable  points  in  their  favor,  and  for  that  reason  they  are  uni- 
versally adopted  in  Europe.  In  the  first  place  this  form  admits 
of  a  greater  amount  of  light  than  the  erecting  eye-piece.  It 
also  allows  a  longer  focal  length  to  the  object  glass,  which  is 
very  important  in  correcting  spherical  aberration,  besides  in- 
creasing the  magnifying  power,  which  is  a  value  dependent 
upon  the  ratio  of  the  focal  lengths  of  the  object  glass  and  eye- 
piece. 

We  have  always  considered  this  inverting  form  the  more 
advantageous  of  the  two;  and  we  are  convinced  that  if  our  en- 
gineers would  accustom  themselves  to  its  use,  it  would  finally 
be  preferred.  There  is  absolutely  no  difficulty  in  the  inverted 
position  of  objects,  and  it  is  remarkable  with  how  little  effort 
the  mind  adjusts  itself  to  it,  so  that  the  work  may  be  done  just 
as  expeditiously  as  though  the  observer  saw  the  objects  erect. 

But,  as  the  erecting  eye-piece  is  in  general  demand,  we  do 
not  intend  to  introduce  the  inverting  one;  all  that  we  wish  to 
point  out  is  that  the  latter  possesses  many  advantages  not  gen- 
erally sufficiently  considered,  and  that  seeing  objects  upside 
down  is  not  an  obstacle  at  all,  for  upside  down  and  right  side 
up  are  only  relative  impressions,  which  impose  no  task  upon 
the  brain.  If  the  professors  of  civil  engineering  in  our  colleges 
would  draw  more  attention  to  these  facts,  the  results  would  soon 
be  quite  gratifying. 

The  erecting  or  terrestrial  eye-pieces  require  four  lenses, 
placed  so  as  to  correct  the  chromatic  aberration.  In  this  form 
the  inverted  image  of  the  object  glass  is  again  inverted,  and  an 
erect  one  is  created  between  the  third  and  fourth  lens,  which  is 
viewed  and  magnified  by  the  fourth.  This  is  the  form  used 
for  our  transits  and  levels,  and  we  can  again  insure  our  patrons 
that  in  this  line  nothing  better  is  produced.  The  optical  pow- 
ers of  the  telescope  are  in  perfect  keeping  with  the  accuracy  of 


34  MODERN    SURVEYING    INSTRUMENTS. 

the  centers,  graduation  and  spirit  levels,  insuring  a  complete 
reliability  and  harmony  in  every  part  of  the  instrument  for  the 
most  refined  surveying  work. 

The  eye-piece  (always  erect  unless  specially  ordered)  is  so 
arranged  as  to  permit  its  easy  removal,  if  necessary,  by  simply 
unscrewing  it.  In  replacing,  it  should  always  be  well  tightened 
up.  It  is  movable  in  and  out  by  a  revolving  motion,  turning 
the  cap  about  one-sixth  of  a  revolution  backward  or  forward — 
a  manner  which  affords  a  finer  and  more  precise  focusing  of  the 
cross-wires  than  by  means  of  a  rack  and  pinion. 

Having  reviewed  generally  the  optical  details  of  the  tele- 
scope, we  shall  describe  in  a  few  words  the  mechanical  construc- 
tion of  its  other  parts. 

d.     Other  Parts  of  Telescope. 

The  slide,  to  which  the  object  is  attached,  fits  directly  in  the 
outside  or  body  of  the  tube.  Particular  attention  is  paid  to 
this  part  to  prevent  even  the  slightest  shake,  and  still  procure 
an  equal  and  sure  motion,  which  is  absolutely  necessary,  as  no 
true  adjustment  of  the  line  of  collimation  is  possible  otherwise. 
The  motion  is  given  by  a  rack  and  pinion. 

The  sliding  tube  is  protected  from  dust  and  dirt  by  an  ex- 
terior metal  cylinder,  called  the  slide  protector. 

A  sun  shade  is  provided  for  the  objective,  which  should  al- 
ways be  attached,  as  the  telescope,  when  focused  to  mean  dis- 
tance, is  balanced  with  it;  and  a  cap  is  provided  for  the  protec- 
tion of  the  objective  when  not  in  use. 

The  cross-wire  frame  is  suspended  in  the  tube  by  four 
capstanheaded-screws,  by  which  it  is  adjusted,  the  frame  being 
so  constructed  that  the  cross-wires  cannot  be  torn,  in  case  the 
adjusting  screws  are  tightened  too  much. 

The  spider  iveb  used  for  our  instruments  is  properly  treated 
to  avoid  all  twist,  and  to  prevent  its  lengthening  and  becoming 
crooked  in  damp  weather;  it  cannot  become  loose,  as  it  is  well 
secured. 

For  mining  and  tunnel  transits  we  can  provide  proper 
means  for  illuminating  the  cross-wires  —  an  arrangement  that 
is  readily  supplied  upon  application. 


THE    A.    LIETZ    COMPANY.  35 

Quite  a  number  of  glass  diaphragms  have  been  cut  by 
us  for  the  United  States  Coast  and  Geodetic  Survey.  In- 
stead of  the  spider  webs,  a  small  disc  of  very  thin  glass  is 
fastened  to  the  diaphragm,  on  which  fine  lines  have  been  drawn 
with  a  diamond.  It  is  readily  seen  that  these  cannot  get  out 
of  shape,  and  for  stadia  measurements  we  think  them  of  great 
advantage.  The  only  drawback  is  that  small  particles  of  dust 
may  settle  on  the  glass  disc,  and,  as  they  are  in  the  focus  of  the 
eye-piece,  they  will  be  constantly  visible  to  the  observer. 

We  make  no  extra  charge  for  putting  these  diaphragms 
into  our  new  instruments,  if  ordered  in  time. 

Stadia  hairs  are  placed  in  all  our  transits  (and  levels),  unless 
ordered  without.  We  have  superior  facilities  for  setting  them 
with  great  precision  to  any  desired  ratio  between  distance  and 
rod  reading.  It  is  customary  to  place  them  so  that  they  shall 
read  1  foot  on  the  rod  for  a  distance  of  100  feet,  and  to  this 
measure  we  always  have  them  in  our  stock  on  hand. 

The  stadia  hairs  may  be  fixed  or  adjustable.  We  advise  the 
fixed,  as  they  are  less  liable  to  change  their  distance.-  In  an 
adjustable  set  the  observer  is  never  certain  that  the  position  of 
the  wires  has  remained  unchanged.  We  have  constructed  a 
delicate  optical  and  mechanical  apparatus  for  fixing  stadia  hairs 
accurately  to  any  proportion;  and  by  means  of  our  powerful 
telescope,  which  has  superior  optical  qualities,  we  can  safely  say 
that,  with  proper  care  and  a  little  experience  in  that  method  of 
measuring,  very  satisfactory  results  may  be  obtained.  The 
facilities  for  measuring  across  inaccessible  places,  and  the  speed 
with  which  it  enables  one  to  get  distances,  has  brought  this 
method  into  deserved  prominence  with  our  engineers.  For 
topographical  surveys  it  is  indispensable. 

For  the  benefit  of  our  patrons  we  have  added  a  short 
treatise  on  stadia  measurements,  together  with  a  table  for  cor- 
recting the  observed  reading  to  the  horizontal  distance  and  dif- 
ference in  level,  which  see  in  Part  III. 

When  purchasing  a  new  instrument,  it  is  advisable  to  get 
one  that  has  fixed  stadia  wires,  which  increases  the  cost  only 
$3,  while  we  charge  $10  to  put  them  into  a  transit  sent  to  us 
subsequently. 


36  MODERN    SURVEYING    INSTRUMENTS. 

In  sighting  with  the  telescope  it  is  of  considerable  advantage 
to  have  it  reversible,  and  our  transits  are  made  so  as  to  allow  this 
free  revolution  in  a  vertical  plane.  The  telescope  balances  ac- 
curately when  in  focus  to  mean  distance,  the  friction  in  the 
bearings  being  shaded  to  such  a  degree  of  nicety  that  it  shall 
neither  work  too  hard  nor  too  loose  —  a  feature  which  ought  to 
have  very  close  attention. 

e.      General  Remarks  about  Telescopes. 

When  selecting  or  examining  an  instrument,  the  engineer 
should  be  particularly  careful  to  test  the  qualities  of  the  tele- 
scope. 

It  should  have  sufficient  magnifying  power  to  correspond 
with  the  finer  qualities  of  the  graduation,  axis,  centers,  spirit 
levels,  etc.,  of  the  instrument.  There  can  be  no  doubt  that 
the  excellencies  of  each  detail  must  compare  with  that  of  any 
other. 

Now,  by  using  a  low-power  telescope,  the  defects  of  an 
inferior  instrument  may  be  hidden,  or  left  undiscoverable ,  and  for 
this  reason  they  will  always  be  found  in  articles  of  lower  grade. 
Had  such  an  instrument  lenses  of  sufficient  magnifying  power, 
the  defects  would  become  apparent  to  the  engineer  at  once.  We 
lay  the  greatest  importance  upon  these  facts,  and  for  this  reason 
call  particular  attention  to  them.  Scrutinize  the  optical  abilities 
of  the  telescope,  and  you  will  obtain  the  character  of  the  ivhole  in- 
strument. 

For  obvious  reasons,  some  makers  —  but  more  especially 
dealers  —  give  the  magnifying  power  of  the  telescopes  of  their 
instruments  much  higher  than  it  really  is.  An  engineer  should, 
therefore,  be  careful  to  convince  himself  of  the  real  magnifying 
power  before  making  a  purchase.  He  will  find  it  much  to  his 
interest  to  do  so. 

We  have  found  that  the  power  of  first-class  instruments 
should  be  about  twice  as  many  diameters  as  the  length  of  tele- 
scope expressed  in  inches.  In  inverting  telescopes  it  may  be 
materially  increased,  which  shows  again  that  they  are  of  con- 
siderable importance  in  very  high  grade  instruments. 

In  another  place  we  have  added  a  practical  method  for  find- 
ing the  magnifying  power  of  a  telescope,  to  which  we  would 


THE    A.    LIETZ    COMPANY.  37 

advise  our  engineers  to  give  some  attention,  and  to  make  use 
of  when  about  to  choose  an  instrument. 

We  have  already  pointed  out  the  importance  of  perfectly 
centering  the  lenses,  especially  the  objective.  If  this  is  not 
properly  attended  to,  the  adjustment  can  never  be  perfected  for 
long  and  short  distances. 

We  have  heard  many  complaints  from  engineers  about  the 
change  in  adjustment,  and  after  careful  examination  we  have 
found  that  the  adjustments  remained  intact,  but  that  the  fault 
lay  in  the  objective,  which  had  not  been  correctly  centered. 
We  take  great  pains  to  center  our  object  glasses  perfectly,  and  to 
insert  the  lenses  in  such  a  manner  that  if  taken  out  they  may 
be  replaced  in  the  old  position,  which  is  secured  by  a  notch  and 
a  pin.  It  is  not  advisable  for  engineers,  however,  to  take  these 
lenses  from  the  cell,  as  their  cleaning  may  be  effected  without 
removing  them. 

Reverting  again  to  the  magnifying  power  of  telescopes,  it 
may  be  asserted  that  an  increase  thereof  reduces  the  field.  This 
is  no  defect,  if  the  size  of  the  latter  is  retained  large  enough  to 
admit  of  stadia  lines  so  placed  as  to  read  1:100.  We  often 
leave  the  field  much  larger,  however,  in  which  case  there  ap- 
pears just  a  slight  dimness  at  the  extreme  border;  this  is  unim- 
portant, for  it  does  not  retract  any  of  the  virtues  of  the  glass, 
and  possesses,  if  anything,  an  advantage  of  finding  an  object 
more  readily. 

The  quality  of  some  of  the  telescopes  of  our  best  makers 
has  often  been  questioned  by  competent  engineers  on  account 
of  a  peculiar  haze  ascribed  to  the  glass.  This  was  found  to  be 
caused  by  a  small  film  of  moisture,  which  settles  between  the 
crown  and  the  flint,  and  is  not  visible  to  the  naked  eye.  We 
have  been  convinced,  by  advising  with  our  optician,  that  the 
crown  and  flint  glasses  should  always  be  connected  with  balsam. 
This  does  not  decrease  the  amount  of  light,  as  formerly  thought, 
but,  on  the  contrary,  it  has  advantages  of  clearness,  in  that  it 
prevents  foreign  matter  from  settling  between  the  lenses,  which 
always  destroys  the  image;  the  refrangibility,  too,  is  under 
more  favorable  conditions  in  the  balsam. 


38  MODERN    SURVEYING    INSTRUMENTS. 

Extra  Accessories  for  the  Transit, 

There  are  a  number  of  additions  made  for  transits  used  for 
special  purposes,  and  these  we  keep  on  hand,  and  supply  them 
when  called  for. 

For  laying  off  right -angles,  for  instance,  we  can  make  any 
provision,  if  the  customer  will  order  it  in  time.  In  fact,  any  of 
the  accessories,  not  usual  in  the  ordinary  complete  field  instru- 
ment, will  be  made  as  an  extra  if  our  patrons  will  notify  us, 

For  the  solar  attachment  we  provide  a  block  with  a  thread 
on  the  telescope  axis  to  receive  the  beautiful  little  apparatus 
known  as  the  ' '  Saegmuller  Solar  "  of  which  a  complete  descrip- 
tion will  be  found  in  Part  III. 

The  Finish. 

This  is  made  to  give  the  instrument  an  elegant,  tasteful 
appearance,  without  adopting  a  color  glaring  to  the  eye.  Our 
instruments  are  finished  in  a  number  of  hues,  and  may  be 
bronzed  to  the  special  taste  of  the  purchaser,  if  he  chooses  to 
order  it. 

Size  of  Transit. 

The  dimensions  and  proportions  of  the  several  parts  of  the 
transit  are  given  in  Part  IV  of  this  catalogue,  where  the  differ- 
ent sizes  and  varieties  of  instruments  made  are  described  more 
in  detail. 

Packing. 

This  is  not  at  all  an  unimportant  feature.  Our  transit  is 
easily  taken  from  the  tripod  by  means  of  the  Lietz  friction 
coupling  already  described,  and  set  upon  a  wooden  slide,  to 
which  it  is  fastened  by  means  of  two  thumb  screws  and  wooden, 
clutches  —  a  manipulation  requiring  but  a  moment's  time. 
Nothing  is  taken  from  the  instrument  except  the  shade — it  re- 
mains a  complete  whole  from  the  base-plate  to  the  top  of  the 
telescope.  The  board  slides  into  the  box  with  the  transit  in  an 
upright  position,  with  the  clamps  secured  to  keep  it  from  turn- 
ing. An  extra  place  is  provided  for  the  solar  attachment,  if 
there  be  one.  The  door  may  then  be  locked,  and  the  instru- 
ment is  absolutely  safe,  with  the  least  effort  of  packing  and  ad- 
justing in  the  box. 


THE    A.    LIETZ    COMPANY.  39 

Rubber  cushions  are  provided  at  the  bottom  of  the  case,  to 
take  up  any  sudden  jar  or  jolt  to  which  it  may  be  exposed  dur- 
ing transportation. 

A  rubber  bag,  or  a  silken  one,  may  be  had  as  an  extra  to 
each  instrument,  as  well  as  a  bottle  of  fine  watch  oil  for  lubri- 
cation of  centers,  etc.,  and  camel-hair  brushes  for  dusting. 
Likewise  are  a  number  of  adjusting  pins  supplied. 

The  Tripod. 

We  have  adopted  the  new  form  of  split  leg — a  construction 
which  combines  the  greatest  stiffness  and  strength  with  the 
least  weight.  The  old  form  of  the  heavy  solid  leg  has  long 
since  been  abandoned,  and  we  no  longer  make  such  a  tripod, 
unless  specially  ordered  by  some  conservative  customer,  or  for 
very  small  instruments.  We  aim  to  reduce  the  weight  of  every- 
thing, without  sacrificing  steadiness  or  strength  in  any  partic- 
ular, and  that  the  split  leg  meets  these  conditions  better  than 
the  solid  one  must  stand  to  reason. 

The  very  best  white  ash  is  chosen  and  carefully  worked. 
Instead  of  fitting  the  leg  between  two  brass  cheeks,  we  fit  one 
cheek  in  the  leg.  In  the  older  construction  it  frequently  hap- 
pened, in  drawing  the  bolts  closer  to  tighten  a  loose  leg,  that 
the  cheeks  would  spring  the  plate,  or  weaken  the  screws  that 
hold  it.  This  is  entirely  obviated  by  the  new  arrangement  of 
these  parts,  for  the  tightening  can  110  longer  affect  the  plate  in. 
the  least.  While  in  the  former  the  leg  would  only  fit  at  the 
lower  part  of  the  cheeks  when  drawn  in  by  the  bolt,  it  will  al- 
ways fit  the  whole  surface  of  the  cheek  in  the  plan  we  follow, 
and  after  ten  years'  use  it  will  be  just  as  steady  as  when  new. 

The  shoes  are  made  on  a  gradual  taper  to  a  sharp  point,  and 
securely  fastened  to  the  leg.  They  are  provided  with  a  projec- 
tion for  pressing  upon  with  the  foot  when  setting  up. 

The  large  transit  and  the  level  fit  the  same  tripod— in  fact, 
any  Lietz  instrument  may  be  readily  fitted  upon  the  tripod  we 
manufacture,  for  the  adjustment  of  the  friction  coupling  allows 
a  perfect  accommodation  to  any  slight  variation  in  the  parts  of 
the  base-plate. 


40  MODERN    SURVEYING    INSTRUMENTS. 

LEVELING   INSTRUMENTS. 

The  A.  Lietz  Company  manufactures  two  different  varieties, 
which  are  constantly  kept  in  stock,  the  Y-level  and  the  dumpy 
level. 

In  the  manner  of  making  these  instruments,  much  that  has 
been  said  of  the  transit  will  hold  good  here,  and  need  not  be 
repeated. 

The  three  main  qualities  to  be  secured  in  a  level  are: 
stability,  a  sensitive  bubble  and  a  poiverful  telescope. 

To  secure  the  first,  we  need  only  refer  to  the  solid  construc- 
tion of  the  star-shaped  casting  through  which  the  leveling  screws 
operate,  already  described  in  speaking  of  that  feature  in  the 
transit.  The  Lietz  coupling,  too,  plays  an  important  part  here, 
for  we  can  make  the  tripod  connection  absolutely  rigid. 

The  center,  or  spindle,  is  almost  three  and  one-half  inches 
long,  and  is  continued  through  the  clamp  up  to  the  bar,  which 
enables  us  to  bring  the  center  of  gravity  as  near  as  possible  to 
the  tripod -head.  Great  care  is  exercised  in  fitting  the  center  to 
the  socket,  and,  being  made  of  steel,  it  must  be  apparent  that 
it  is  an  utter  impossibility  to  wear  out  these  parts  even  by  fifty 
years'  constant  use.  The  liability  of  bending  the  spindle,  so 
common  an  accident  with  instruments  having  brass  centers,  and 
the  fretting  of  the  same,  also  likely  to  happen  at  times,  is  al- 
together avoided  by  a  steel  center.  The  fact  is,  every  level 
ought  to  have  one,  and  its  omission  is  simply  due  to  the  fact 
that  it  is  more  expensive  to  manufacture. 

The  reasons  for  having  a  sensitive  bubble  have  also  been 
carefully  set  forth  heretofore.  Accurate  work  cannot  be  done 
with  a  sluggish  bubble.  No  matter  how  much  the  virtues  of 
the  staying  qualities  may  be  extolled  by  some  men,  they  are  not 
fit  for  refined  work  if  they  do  not  answer  the  slightest  touch  of 
the  leveling  screw.  If  you  can  give  a  screw  a  twist  or  two  be- 
fore the  bubble  loses  its  peaceful  equanimity,  the  work  in  hand 
would  not  be  likely  to  inspire  any  great  confidence. 

Our  level  tube  is  curved,  so  as  to  give  for  every  two  minutes 
of  arc  a  one  -  inch  motion  of  the  bubble.  A  refined  level 
of  this  character,  however,  will  only  do  good  service  in 


THE    A.     LIETZ    COMPANY.  4l 

an  instrument  having  perfect  steadiness  and  a  powerful  and 
sharply  defining  telescope.  If  placed  in  a  level  so  constructed 
as  to  be  topheavy,  or  in  one  whose  center  is  frequently  exposed 
by  being  a  part  of  the  tripod  head — and  therefore  liable  to  col- 
lect dust  both  on  the  cone  and  in  the  socket,  introducing  sources 
of  error  after  every  detachment — then  it  will  indeed  prove  very 
annoying,  should  an  active  bubble  accompany  such  an  instru- 
ment. These  structural  defects  are  probably  the  cause  why 
many  of  our  engineers  are  prejudiced  against  sensitive  levels, 
and  prefer  a  sluggish  or  dull  one.  We  can  only  assure  the 
reader  again  that  a  lively  bubble,  even  if  a  little  out  of  center 
by  reversing  the  instrument,  will  still  accomplish  better  results 
than  an  inactive  one — one  that  gives  the  instrument  an  appear- 
ance of  steadiness,  which  in  reality  it  is  far  from  possessing. 
An  engineer  only  deceives  himself  if  he  trusts  to  a  slowly-acting 
level,  which  gives  apparent  satisfaction  by  concealing  the  errors 
that  a  sensitive  one  would  soon  indicate.  A  well-made  instru- 
ment never  suffers  by  having  its  qualities  exposed  by  a  high- 
grade  bubble. 

The  level  telescope  should  have  power  and  definition.  It  is 
hardly  necessary  to  make  that  statement,  after  all  that  has  been 
said  on  this  subject  in  a  previous  chapter.  It  has  been  our 
earnest  endeavor  to  obtain  these  results,  without  increasing  the 
dimensions  of  the  telescope  and  the  other  parts  of  the  instru- 
ment, beyond  the  proper  limits  for  steadiness  and  portability. 
A  length  of.  eighteen  inches  we.  have  found  to  give  the  most 
advantageous  results.  Experience  has  shown  us,  that  although 
an  increased  length  adds  to  the  magnifying  power,  it  would 
only  be  of  value  if  the  other  parts  of  the  instrument  were 
enlarged  in  proportion,  which,  on  the  other  hand,  would  make 
it  too  heavy  for  convenience  in  carrying.  While  in  some  ex- 
ceptional cases  such  an  instrument  might  be  preferable,  we 
believe  that  with  our  18-inch  level  even  the  most  extensive  re- 
quirements in  engineering  are  fully  met. 

Our  new  and  improved  eye-piece,  and  the  use  of  an  ob- 
jective of  larger  diameter  than  ordinarily  found,  enable  us 
to  obtain  a  magnifying  power  of  33.  An  increase  of  diame- 
ter adds  very  little  to  the  weight  of  the  telescope,  and  does  not 


42  MODERN  SURVEYING  INSTRUMENTS. 

require  a  longer  bar  and  larger  plates,  as  an  increase  in  length 
necessarily  would,  to  retain  steadiness.  An  aperture  of  1| 
inches,  used  to  its  full  value,  affords  a  high  illumination  with 
the  above-mentioned  power,  as  the  tube  is  large  enough  to  let 
all  the  rays  proceeding  from  the  object  glass  pass  through  to  the 
field  of  view  —  an  important  point  disregarded  by  a  number  of 
manufacturers. 

The  diameter  of  the  aperture  of  the  object  glass  divided  by 
the  power,  gives  the  diameter  of  the  pencil  of  light  entering  the 
eye.  In  our  telescope  we  obtain,  therefore,  1|  -s-  33  =  ^T  of  an 
inch,  which  shows  that  power  and  brightness  are  in  accordance 
with  optical  law.  To  force  the  power  beyond  these  limits  we 
cannot  conscientiously  do,  as  that  would  be  allowable  only 
under  certain  circumstances  —  such  as  a  perfectly  clear  atmos- 
phere with  a  strong  illumination  of  the  object. 

The  collars,  upon  which  the  telescope  rests  in  the  Ys,  are 
made  of  the  hardest  bell  metal,  and  admit  of  a  position  in  either 
direction,  that  is,  the  telescope  is  reversible.  The  very  first 
requisite  is  that  these  collars  must  be  of  exactly  equal  diameter 
and  perfect  cylinders.  If  this  be  not  the  case,  the  line  of  colli- 
mation  will  not  be  parallel  to  a  tangent  of  the  bubble's  curve  at 
its  highest  point,  when  the  latter  indicates  a  horizontal  position, 
and,  for  this  reason,  a  true  level  cannot  be  obtained  with  such 
an  instrument. 

It  is  very  often  believed  that  in  the  course  of  adjusting  the 
Y-level,  by  reversal  of  telescope  and  revolving  on  center,  the 
bubble  will  indicate  any  inequality  of  the  collars,  but  this  is  by 
no  means  true.  If  the  Ys  are  both  filed  out  to  the  same  angle 
(this  is  generally  the  case,  or  at  least  very  nearly  so,  as  most 
makers  file  them  out  by  means  of  gauges),  the  inequality  of  the 
collars  may  be  quite  appreciable,  and  yet  the  instrument  will 
be  adjustable  in  all  its  parts;  in  other  words,  it  may  be  so  ad- 
justed that  the  bubble  on  all  reversals  in  the  Ys  and  revolutions 
on  centre,  will  always  give  the  same  reading  at  both  ends,  that 
is,  indicate  a  true  horizontal  position.  A  final  test  is  necessa- 
ry, therefore,  after  the  instrument  is  properly  adjusted,  to  as- 
certain the  equality  of  the  collars.  This  will  be  mentioned 
further  on  under  the  head  of  adjustments. 


THE    A.     LIETZ    COMPANY.  43 

Similar  causes  for  error  are  introduced  if  a  particle  of  sand 
lodges"  between  the  collar  and  Y,  which  illustrates  the  necessity 
of  keeping  these  parts  free  from  all  dust  and  dirt. 

It  is  readily  demonstrated  to  what  considerable  differences 
any  slight  inequality  in  the  diameters  of  the  collars  may  give 
rise  to,  but  the  space  here  will  not  permit  of  a  mathematical 
discussion  of  the  subject. 

We  have  carefully  explained  this  defect,  owing  to  the  con- 
viction on  our  part  that  it  is  a  much  more  common  one  than  is 
generally  suspected.  Numerous  cases  have  come  under  our  ob- 
servation, where  this  fault  existed  in  a  remarkable  degree.  And 
in  the  perusal  of  many  works  on  engineering  and  surveying, 
we  have  noticed  very  few  that  call  attention  to  this  material 
defect,  and  still  less  that  give  a  correct  test  for  it. 

We  are  aware  that  accurate  leveling  may  be  done  with  a 
level  out  of  adjustment,  if  the  utmost  precaution  is  taken  to 
have  equi-distant  fore-aiid  back-sights.  But  looking  at  it  from 
this  point  of  view,  why  not  use  the  dumpy  level  then,  instead 
of  the  more  costly  Y-level? 

The  Finish  is  made  to  give  the  instrument  an  elegant  ap- 
pearance, and  yet  obtain  all  the  qualities  alluded  to  in  a  previ- 
ous discussion  of  the  same  subject.  The  telescope  is  usually 
cloth  finished  to  avoid  that  unequal  expansion  of  the  metal  here- 
tofore mentioned.  This  finish  is  of  a  color  pleasing  to  the  eye, 
is  applied  so  that  it  remains  intact  for  a  long  time,  and  if  some- 
what worn  after  a  long  period  of  exposure,  it  can  be  readily  re- 
applied  without  difficulty  at  a  trifling  expenditure.  The  cloth 
finish  is  a  modern  feature,  and  one  that  is  so  universally  pre- 
ferred, that  we  have  no  hesitation  in  recommending  it  to  our 
patrons  as  worthy  of  their  consideration.  However,  we  keep  in 
stock  the  bronzed  and  lacquered,  as  well  as  the  cloth -finished 
level  telescopes,  so  that  the  customer  may  have  his  choice  in 
the  matter. 

The  level  telescope  is  supplied  with  a  slide  protector  and 
with  a  sunshade;  the  latter  should  always  be  put  on  to  balance 
it  evenly.  A  cap  is  also  provided  for  the  objective  and  a  shut- 
ter for  the  eye-lens. 

In  all  other  matters  the  transit  details  obtain  here  also. 


44  MODERN  SURVEYING  INSTRUMENTS. 

Fixed  stadia  ivires  are  supplied,  set  to  read  1: 100,  for  which 
an  extra  charge  is  made. 

The  center  movement  is  checked  and  regulated  by  a  clamp 
and  tangent  screiv,  exactly  similar  to  those  of  the  transit. 

Other  useful  accessories  are  attached,  but  any  feature  not 
usually  found  in  the  Y-level,  must  be  ordered  beforehand.  If 
desired,  we  place  agate  fittings  in  the  Ys  for  the  collar  contact, 
but  for  this  we  also  make  an  extra  charge. 

We  are  likewise  in  a  position  to  make,  but  upon  order  only, 
levels  of  precision  for  the  most  exact  work  that  the  geodetic  sur- 
veyor is  called  upon  to  perform.  These  are  provided  with  all 
the  delicate  details  that  such  an  instrument  must  possess.  We 
invite  correspondence  upon  the  subject  of  geodetic  instruments, 
and  will  cheerfully  furnish  prices  after  consulting  with  our 
patron  upon  the  nature  and  character  of  the  instrument  re- 
quired. 

The  packing  in  the  case  has  been  made  so  as  to  assure  safe- 
ty in  transportation,  with  the  least  trouble  and  inconvenience 
to  the  operator.  The  level  is  taken  from  the  tripod  by  a  third 
of  a  revolution  of  the  base  plate,  which  undoes  the  Lietz  Coup- 
ling. It  is  let  down  to  stand  upright  in  the  box,  the  telescope 
having  been  removed  from  the  Ys  and  placed  with  its  collars 
upon  padded  brackets  at  the  side  of  the  case,  when  the  closing 
of  the  lid  holds  everything  firmly  in  place.  In  all  minor  details 
the  level  box  is  similar  to  the  transit  case,  every  means  being 
employed  to  insure  absolute  safety. 

The  Dumpy  Level. 

In  this  instrument  the  aim  has  been  to  construct  it  in  such 
a  manner  that  it  shall  be  as  compact  as  possible  by  dispensing 
with  certain  features  of  the  Y-level,  not  absolutely  necessary  in 
order  to  do  good  and  reliable  work. 

The  principles  governing  its  construction  are  the  same  as 
those  that  obtain  in  the  more  elaborate  Y-instrument. 

The  telescope  is  permanently  held  by  two  vertical  arms  at- 
tached to  the  level  bar,  and  cannot  be  taken  therefrom.  The 
level  tube  rests  upon  these  arms,  over  the  telescope,  and  is  also 
fixed.  The  telescope  tube  is  thereby  brought  as  close  as  pos- 


THE    A.    LIETZ    COMPANY.  45 

sible  to  the  tripod  head,  which  is  a  desirable  characteristic.  All 
the  other  features  remain  the  same  as  in  the  Y-level  construc- 
tion. 

This  instrument,  which  is  almost  exclusively  used  in  Eu- 
rope, has  not  yet  met  with  that  favor  by  American  engineers, 
which  its  simplicity  and  accuracy  so  justly  deserve.  This  is 
due  partly  to  its  greater  inconvenience  in  adjusting  as  com- 
pared with  the  Y-level,  and  partly  on.  account  of  defective  con- 
struction, inferior  tejescope  and  other  neglected  details,  which 
usually  obtain  in  instruments  of  this  kind. 

We  are  confident  that  a  dumpy  level  possessing  a  good  tel- 
escope, sensitive  bubble  and  stability,  will  do  just  as  good  work 
as  the  more  costly  Y-level.  While  the  adjustment  of  the  latter 
is  made  more  readily,  the  former  will  retain  it  longer. 

Our  dumpy  level  has  a  bronze  center,  a  15 -inch  telescope, 
and  a  vial  of  such  curvature,  as  to  give  for  each  inch  of  mo- 
tion of  the  bubble  an  angle  of  three  minutes. 

There  is  no  clamp  or  tangent  screw  to  this  form  unless  or- 
dered by  the  customer. 

Bar,  telescope  and  vial  case  are  cloth  finished,  and  the  lat- 
ter may  be  provided  with  a  folding  mirror,  which  acts  as  an 
important  protection  to  the  more  exposed  spirit  level  when  shut 
down,  or  as  an  indicator  to  the  observer  at  the  eye-piece,  of  the 
exact  position  of  the  bubble,  when  elevated. 

The  stadia  hairs  may  also  be  supplied  to  the  dumpy  level. 

Other  Levels  on  Sale. 

In  addition  to  the  high  grade  instruments  manufactured  in 
our  shop,  we  keep  on  hand  a  supply  of  smaller  and  less  costly 
goods,  imported  from  Germany.  With  these  instruments  work 
maybe  done  by  the  ditcher,  irrigator,  contractor,  grader,  farmer, 
dike  builder,  gardener,  plumber,  architect,  forester  and  military 
man,  sufficiently  precise  for  many  ordinary  purposes,  wherein 
great  accuracy  is  not  required. 

For  a  more  detailed  description  of  these  instruments,  see 
Part  IV  of  this  catalogue,  containing  a  price  list  of  articles  on 
sale. 


46  MODERN    SURVEYING    INSTRUMENTS. 

Remarks. 

In  the  foregoing  we  have  endeavored  to  give  the  reader 
a  fair  idea  of  the  principal  engineering  instruments  made 
by  this  firm.  We  desire  to  convince  our  future  customers 
—  our  old  patrons  we  have  long  since  convinced  —  that  we  are 
huilding  conscientiously  upon  scientific  principles,  that  every 
part  and  detail  has  been  carefully  studied  to  meet  the  require- 
ments of  our  engineering  fraternity,  of  the  climate,  and  of  all 
those  conditions  that  influence  the  shape  and  character  of  every 
feature  of  the  surveying  instrument.  It  must  permit  of  all  op- 
erations at  the  least  expenditure  of  time,  it  must  be  compact,  it 
must  be  light,  it  must  be  absolutely  accurate,  it  must  be  rigid, 
it  must  be  stable  and  it  must  possess  strength.  And  wherever 
a  possible  improvement  is  suggested  in  any  detail,  it  must  be 
applied  at  once  and  tested  as  to  its  probable  merits,  and  if  it 
prove  of  value,  no  time  must  be  lost  in  introducing  it.  These 
are  the  principles  that  have  governed  the  manufacture  of  the 
articles  which  we  have  brought  to  your  notice. 

New  improvements  have  always  had  our  attention,  without 
any  regard  of  the  expenses  incurred  in  experimenting.  We 
need  only  refer  to  the  recent  introduction  of  aluminium  in  the 
manufacture  of  surveying  instruments,  which,  we  are  fully  con- 
vinced, has  been  crowned  with  success,  to  prove  to  our  patrons 
that  we  never  allow  any  conservative  notion  to  rule  the  estab- 
lishment. The  particulars  of  this  new  field  of  manufacture 
will  be  found  in  another  chapter  of  this  part  of  the  Manual. 

With  the  object  constantly  in  view  to  make  only  the  very 
best  article  that  can  be  procured  anywhere,  and  ever  ready  to 
introduce  improvements  and  to  experiment  with  suggestions 
that  may  lead  to  them,  our  instruments  are  held  at  a  price  that 
is  commensurate  with  their  qualities.  Their  values  are  rated 
by  those  current  among  first-class  instrument  makers;  they  are 
no  more,  but  they  are  no  less.  We  do  not  handle  cheap  goods, 
and  the  trade  that  we  are  most  anxious  to  please  is  that  ivilling 
to  pay  a  fair  price  for  a  number-one  article.  With  us  the  value 
of  an  instrument  depends  upon  the  features  involved  and  the 
accessories  supplied,  and  never  upon  the  workmanship;  that  is 


THE    A.    LIETZ    COMPANY.  47 

always  first-class,  from  the  simplest  compass  transit  to  the  most 
improved  transit  theodolite. 

It  was  our  purpose  to  describe  in  this  catalogue  only  the 
instruments  for  which  there  exists  the  greatest  demand,  and  for 
this  reason  we  do  not  intend,  at  this  time,  to  enter  into  any 
detail  of  the  manufacture  of  other  scientific  apparatus  that  we 
are  in  position  to  furnish  upon  due  notice. 

Theodolites  of  the  highest  grade  for  the  most  exact  pur- 
pose, reading  with  micrometers  to  the  most  refined  division,  will 
be  made  upon  order  to  any  desired  shape  and  design,  and  with 
every  required  accessory.  This  also  holds  good  for  all  nautical 
apparatus,  such  as  sextants,  three-armed  station  pointers,  logs, 
barometers,  compasses,  marine  glasses,  etc.,  etc. 

We  also  manufacture  the  topographer's  plane-table,  either 
in  its  simplest  form,  as  recently  perfected  by  the  highest  author- 
ities, or  in  its  most  delicate  arrangement  of  parts,  as  devised 
for  work  of  the  greatest  precision  capable  of  being  put  on  paper. 
A  number  of  plane-tables  made  for  our  institutions  of  learning, 
and  for  surveying  departments  of  the  U.  S.  Government,  have 
given  absolute  satisfaction,  as  shown  by  testimonials  in  our 
possession. 

The  modern  improved  plane-table  alidade  is  a  particular 
specialty,  to  which  we  have  given  considerable  time  and  atten- 
tion. This  instrument  has  been  constructed  by  us  of  aluminium, 
which  has  been  a  perfect  success,  proven  by  the  fact  that  one 
of  them  has  been  almost  daily  in  use  for  some  time,  under  very 
trying  conditions,  without  giving  rise  to  the  first  complaint. 
Under  the  head  of  Aluminium  for  Surveying  Instruments,  this 
will  be  again  referred  to.  By  a  combination  of  aluminium  and 
aluminium  bronze,  the  center  of  gravity  of  the  alidade  may  be 
brought  close  to  the  foot  of  the  standard,  which  is  a  very  essen- 
tial point  in  its  construction. 

ALUMINIUM  FOR  SURVEYING  INSTRUMENTS. 

A  great  deal  has  been  said  and  written  about  this  compar- 
atively new  metal  of  late,  so  that  its  characteristics  have  become 
generally  known. 

Its  color  is  a  dull  white,  similar  to  silver,  and  rather  pleas- 


48  MODERN    SURVEYING    INSTRUMENTS. 

ing  to  the  eye.  It  embodies  many  qualities  that  make  it  a  very 
valuable  material  in  the  mechanic  arts.  It  is  quite  soft,  but 
possesses  malleability,  tenacity  and  ductility,  so  that  it  may  be 
made  into  very  thin  sheets,  or  drawn  out  into  fine  wire.  It  is 
a  conductor  of  heat  and  electricity.  One  of  its  principal  feat- 
ures is  that  it  does  not  oxydize  in  the  atmosphere,  and  that  it 
does  not  lose  its  brightness  under  conditions  that  would  tarnish 
silver  and  blacken  it,  for  sulphuretted  hydrogen  or  sulphide  of 
ammonium  do  not  influence  its  color.  But  the  greatest  ad- 
vantage is  its  remarkable  light  weight,  the  specific  gravity  being 
only  2.6,  or  one-fourth  of  that  of  silver,  and  for  this  particular 
quality  its  use  has  been  sought  in  the  manufacture  of  articles 
requiring  small  weight,  ever  since  the  cost  of  its  production  has 
justified  it. 

One  of  the  many  alloys  is  the  so-called  aluminium  bronze, 
which  unites  hardness  with  malleability,  and  is  therefore  ex- 
tensively used  for  many  purposes.  This  alloy,  however,  gains 
little  in  lightness  as  compared  with  the  ordinary  metals. . 

Since  it  has  been  the  constant  aim  to  produce  field  instru- 
ments that  shall  combine  strength  with  the  least  practical 
weight,  there  could  not  have  been  found  a  better  application  for 
aluminium  than  in  the  instrument-maker's  art. 

It  was  necessary  to  experiment  with  it  in  different  direc- 
tions, particularly  as  to  the  proper  alloy  —  it  being  much  too 
soft  in  its  pure  state — that  shall  give  the  required  tensile  strength 
and  stiffness,  make  it  workable  without  fretting,  and  yet  add 
little  to  its  weight.  An  alloy  with  silver  is  now  made  that  fully 
satisfies  these  conditions. 

One  of  the  principal  objections  urged  against  it  in  the 
manufacture  of  surveying  instruments  is,  that  on  account  of 
extreme  lightness  they  would  not  be  steady  enough  in  the 
wind.  This  firm  has  built  a  number  of  transits  and  levels  of 
aluminium,  and,  in  our  opinion,  they  are  quite  as  rigid  as  any 
other,  if  properly  constructed,  care  being  taken  to  adhere  to  the 
old  material  in  such  details  where  it  cannot  be  dispensed  with? 
We  have  found  that  the  stability  of  an  instrument  depends 
more  particularly  upon  the  construction  of  its  lower  parts.  If 
the  combination  of  base-plate  and  leveling  apparatus  be  made 

*  See  Testimonials  for  instruments  made  of  our  aluminum  alloy,  on  fly-leaves. 


THE    A.    LIETZ    COMPANY.  49 

so  that  the  instrument  can  be  rigidly  held,  a  little  more  or  less 
of  wind  surface  is  not  so  important,  as  long  as  every  part  is 
equally  strong.  The  center  of  gravity,  too,  may  be  brought 
down  a  little  lower,  and  that  in  itself  would  tend  to  increase 
its  stability. 

Aluminium  transits  are  made  by  the  A.  Lietz  Company  in 
two  sizes,  being  complete  field  instruments  with  every  accessory. 
The  large  transit  weighs  7  J  pounds,  and  the  small  one  4J  pounds, 
which  reduces  the  weight  about  one-half.  The  construction  is 
precisely  the  same  as  in.  the  instruments  already  described. 

The  base-plate  is  of  composition  metal,  the  inner  center  of 
the  hardest  bell  metal,  and  the  outer  center  of  bronze.  The 
leveling  screws  are  also  of  composition,  as  well  as  the  bearings 
of  the  telescope  axis.  That  means,  that  wherever  any  part  is 
subjected  to  particular  wear  and  friction,  the  old  metal  has  been 
retained,  while  all  the  rest  of  the  instrument  is  made  of  alum- 
inium. 

These  transits  may  either  be  left  in  the  beautiful  natural 
color  of  the  metal,  or  other  shades  may  be  applied.  The  stand- 
ards are  cloth-finished. 

The  Saegmuller  Solar  Attachment  is  now  ma,de  of  aluminium, 
which  can  only  be  an  improvement  in  any  direction,  whether 
its  weight  be  added  to 'the  top  of  a  transit  made  of  the  old  red 
metal,  or  to  one  of  the  new  metal.  Lightness  in  the  solar  at- 
tachment is  a  very  desirable  feature,  and  that  may  be  easily 
obtained  now. 

In  the  Y-level  the  base-plate  and  leveling  screws  are  of 
composition  metal,  the  centers  steel,  the  collars  the  hardest  bell 
metal,  and  the  rest  aluminium.  It  has  an  18-inch  telescope, 
its  weight  being  5J  pounds. 

In  the  dumpy  level  the  same  features  obtain,  except  that  the 
centers  are  of  hard  bell  metal.  Its  length  of  telescope  is  15 
inches,  and  its  weight  4i  pounds. 

Both  levels  are  cloth-finished,  similar  to  those  already  de- 
scribed. 

We  also  manufacture  a  plane-table  alidade  of  aluminium, 
with  a  ruler  of  aluminium  bronze.  This  instrument,  although 
of  the  same  weight  as  one  of  the  ordinary  metal  of  the  same 


50  MODERN    SURVEYING    INSTRUMENTS. 

size,  possesses  the  particular  advantage  of  having  its  center  of 
gravity  as  low  as  it  can  possibly  be  brought  to  the  table,  and 
that  when  placed  upon  the  board  it  will  be  absolutely  stable, 
and  will  not  be  influenced  by  the  wind,  which  causes  the  ordi- 
nary alidade  to  tremble  and  travel  on  the  paper. 

And  this  is  the  reason  why  we  should  object  very  strongly  to  an 
aluminium  rule  in  a  plane-table  alidade.  This  part  of  the  alidade  should 
be  of  heavy  material,  as  well  as  the  lower  part  of  the  standard,  while 
the  rest  may  be  constructed  as  lightly  as  possible.  In  this  case  little  or 
nothing  may  be  gained  in  the  weight,  but  very  much  is  gained  in  sta- 
bility, when  compared  with  an  instrument  made  of  one  metal  through, 
out.  Under  no  condition  should  the  RULE,  which  is  the  BASE  of  the 
structure,  be  made  of  a  light  material. 

After  several  years  of  experience  in  the  construction  of  aluminium 
surveying  instruments,  we  are  ready  to  advocate  the  judicious  use  of 
this  material.  We  have  applied  it  in  transits  and  levels,  and  have 
accomplished  a  saving  in  weight  of  about  50  per  cent.  Great  care  is 
exercised  in  the  proper  distribution  of  the  metal.  We  have  already 
stated  that  in  a  transit  aluminium  is  never  used  in  the  construction  of 
the  base-plate,  centers,  leveling  screws,  clamps,  bearings  of  telescope 
and  all  minor  parts  having  threads.  The  principal  horizontal  members, 
the  plates,  are  of  aluminium,  strongly  ribbed. 

Much  has  been  written  about  its  high  coefficient  of  expansion,  and 
particular  stress  has  been  laid  upon  the  effect  of  unequal  expansion 
necessarily  induced  by  the  use  of  different  metals.  If  this  matter  be 
considered  for  one  moment,  however,  it  will  soon  be  seen  that  practi- 
cally there  can  be  no  serious  result  from  this  source.  In  the  first 
place,  the  difference  between  the  coefficients  of  brass  and  aluminium  is 
altogether  too  small  *  that  the  effect  of  any  possible  distortion  in  ma- 
terial judiciously  placed  need  necessarily  be  feared.  Glass  plays  a  very 
important  part  in  the  make-up  of  a  transit.  The  coefficient  of  expan- 
sion in  glass  is  very  low  (0.8  mm.  per  meter,  raised  100°  C)  and  a  metal 
best  adapted  for  our  purpose  would  be  one  having  the  same  coefficient. 
Now,  as  far  as  brass  and  aluminium  are  concerned,  it  is  readily  seen 
that  there  is  practically  no  difference  in  them  when  compared  with 

*  (The  Physical  Laboratory  of  the  German  Empire  has  established  the  following  :  for 
brass  1.88  mm.  per  meter  of  length,  raised  in  temperature  100°  C  ;  for  aluminium  2.34. 
Our  reductions  are  made  from  these  data.) 


THE    A.    LIETZ    COMPANY.  51 

glass.  As  long  as  glass  is  used,  one  may  as  well  employ  aluminium  as 
brass  for  the  constructive  parts,  for  while  the  expansion  of  the  latter 
exceeds  that  of  glass  0.000072  inches  per  linear  foot  for  1°  Fahrenheit, 
that  of  the  former  does  so  only  by  0.000103. 

Unequal  expansion,  therefore,  is  not  a  source  of  error  that  need 
reasonably  be  feared.  In  an  astronomical  instrument  intended  for  the 
greatest  possible  precision,  we  are  willing  to  concede  every  element  of 
structural  refinement ;  but  in  an  engineer's  transit,  where  a  limit  of 
twenty  seconds  of  arc  is  seldom  exceeded,  and  one  of  thirty  to  sixty 
seconds  all  that  is  ordinarily  required,  the  possible  disadvantage  of  an 
excess  of  10300  part  of  an  inch  in  expansion  per  linear  foot,  in  a  change  of 
temperature  of  100g  Fahrenheit,  is  entirely  overcome  by  the  very  great 
advantage  of  the  reduction  of  the  weight  of  the  whole.  A  small  red 
metal  transit  with  a  5-inch  plate  will  weigh  14£  pounds  with  the  tripod. 
If  this  load  can  be  reduced  to  10|  pounds,  we  are  giving  to  the  field 
engineer  something  that  he  will  appreciate  far  more  than  the  possible 
error  due  to  the  unequal  expansion. 

The  more  vital  objection  to  a  light  instrument — its  greater  un- 
steadiness in  the  wind  when  compared  with  a  heavier  make  —  is  some- 
thing we  have  already  referred  to.  We  have  sold  quite  a  number  of 
aluminium  transits  and  levels,  and  every  one  has  been  a  proof  of  our 
statement  made  two  years  ago :  that  the  stability  depends  more  upon 
the  construction  of  its  base  and  connection  with  the  tripod  than  it  does 
upon  the  weight  of  what  may  be  called  its  superstructure  —  the  part 
above  the  leveling  head. 

We  intend  to  furnish  the  proof  of  this  by  a  systematic  test,  as  we 
are  now  experimenting  with  instruments  of  the  same  make,  same  super- 
ficial area,  but  of  different  weights,  in  strong' wind. 

It  may  also  be  mentioned  incidentally  that  a  fall  will  injure  an 
aluminium  instrument  less  than  if  made  of  red  metal.  Not  only  is  this 
theoretically  correct,  but  our  actual  experience  in  this  line  has  proven 
to  us  the  fact  that  from  ordinary  accidents  the  lighter  instruments  are 
always  less  seriously  injured  than  the  heavier  ones. 

The  testimonials  from  our  customers  will  show  the  public  that  the 
aluminium  instruments  made  by  our  firm  have  given  the  fullest  satis- 
faction, and  have  not  disappointed  our  expectations. 


52  MODERN    SURVEYING    INSTRUMENTS. 

We  are  firmly  convinced  of  the  adaptability  of  aluminium 
for  surveying  instruments,  and  for  that  reason  our  firm  has 
gone  extensively  into  that  branch  of  manufacture,  for  which 
every  facility  has  been  added  recently  to  the  capacities  of  the 
shop.  The  aluminium  instrument  is  fifty  per  cent,  lighter 
than  the  other,  is  just  as  strong,  is  just  as  precise  in  its  work- 
ings, possesses  every  requisite  detail  of  a  complete  field  instru- 
ment, and,  we  claim,  is  just  as  stable.  Those  of  the  engineering 
fraternity  who  have  to  carry  the  transit  all  day,  the  mining  and 
railway  men,  who  climb  the  mountain  sides  during  the  long 
summer  days  from  early  until  dark,  will  not  be  long  in  finding 
out  these  advantages  and  in  putting  them  to  a  severe  test  in 
every  direction. 


CARE  OF  INSTRUMENTS. 

The  greatest  source  of  danger  to  a  delicate  instrument  is 
careless  handling.  It  is  often  subjected  to  violent  usages  for 
which  there  is  absolutely  no  need.  The  rude  way  of  manipu- 
lating its  delicate  parts;  the  unnecessary  display  of  digital 
strength  in  operating  a  clamp;  the  useless  strain  applied  to  the 
leveling  screws;  the  careless  manner  of  carrying  it;  the  rough 
method  of  taking  it  out  of  its  case,  or  replacing  it;  and  the  in- 
cautious closing  of  a  lid  or  door  of  a  box  by  force,  before  the 
instrument  is  somewhat  adjusted  to  its  position;  all  these  are 
sources  of  danger  that  vitiate  its  adjustments  and  cause  no  end 
of  trouble  and  expense.  Although  a  well-made  instrument  is 
so  designed  as  to  stand  many  a  shock  without  direct  injury,  any 
daily  repeated  abuse  is  sure  to  have  its  ill  effect,  from  which 
your  work  must  suffer.  Our  warning  to  be  careful  in  the 
handling  of  your  instrument,  is  therefore  a  well-intended  piece 
of  advice. 

As  the  usefulness  of  a  transit  or  level  may  be  preserved  for 
many  years  by  a  little  attention  to  details,  we  shall  enumer- 


THE    A.    LIETZ    COMPANY.  53 

ate  a  few  of  the  principal  points  which  the  engineer  will  do 
well  to  observe. 

Always  protect  your  instrument  from  rain  by  throwing 
over  it  a  waterproof  bag;  and  if  it  gets  wet  at  all,  clean  it 
thoroughly  after  getting  under  shelter.  It  is  not  well  to  enter 
a  hot  room  from  the  cold  air,  without  giving  it  some  protection. 
The  condensing  vapor  settling  on  the  metal  and  glasses  is  certain 
to  give  rise  to  injuries.  It  is  always  safe  to  place  the  instru- 
ment in  its  case  before  going  into  a  warm  room  in  winter.  It  is  not 
wise  to  leave  your  transit  or  level  exposed  for  hours  to  the  hot 
sun.  Shade  must  be  given  either  by  a  hood  thrown  over  the 
instrument,  or  by  holding  an  umbrella.  Attention  to  these 
points  will  preserve  the  accuracy  of  all  the  delicately  adjusted 
parts,  that  by  an  unequal  expansion  or  contraction  would  be 
certain  to  suffer. 

But,  accidents  are  liable  to  happen,  and  for  that  reason  we 
have  noted  down  a  few  remedies  in  case  of  an  emergency. 

The  general  tendency  in  the  use  of  the  screws  is  to  over- 
strain them.  This  should  never  be  done,  especially  with  the 
cross-wire  screws,  which,  when  brought  up  too  tight,  are  liable 
to  constant  change  and  loss  of  adjustment.  The  leveling  and 
clamp  screws,  if  overstrained,  wear  out  sooner  and  may  show 
fretting.  If  this  takes  place,  they  should  be  taken  out  and 
brushed  with  a  little  coal  oil  or  benzine.  The  nuts  are  best 
cleaned  by  screwing  a  flat  piece  of  soft  wood  through  their  ap- 
ertures. In  putting  them  together  oil  them  slightly. 

Fretting  of  the  centers  and  of  the  telescope-slide  will  inter- 
fere more  with  a  correct  working  of  the  instrument  than  any 
other  part  out  of  order.  They  should  be  watched,  therefore, 
very  closely,  and  as  soon  as  any  rough  motion  manifests  itself, 
it  should  be  remedied  at  once,  if  possible,  by  an  instrument 
maker.  If  this  cannot  be  had,  and  the  fretting  is  in  the  slide, 
first  scrape  and  then  burnish  down  the  place  where  it  frets.  It 
may  also  be  ground  slightly  with  oil  and  very  fine  pumice  stone 
dust,  which  is  best  obtained  by  rubbing  two  pieces  on  each 
other.  After  grinding  them  a  little,  the  tubes  should  be 
cleaned  and  placed  together  again  with  oil  only;  then  move 
them  in  and  out  a  number  of  times,  wipe  the  oil  off,  and 


54  MODERN    SURVEYING    INSTRUMENTS. 

finally  put  them  together  when  dry.  Should  the  fretting 
occur  in  the  centers  (if  properly  made  and  constructed,  so 
that  they  do  not  come  apart  in  detaching  the  instrument 
from  the  tripod,  this  will  never  happen),  employ  the  same 
means;  and  if  this  be  not  effective,  place  a  washer,  made  of 
paper  or  a  thin  card,  between  the  shoulders.  This  will 
cause  a  shake,  making  accuracy  impossible,  and  will  introduce 
errors  of  parallax  in  reading  off,  which  is  better,  however,  than 
to  destroy  the  centers  wholly.  The  best  unguent  for  them  is 
very  fine  watch  oil.  Regarding  our  centers,  we  are  fully  pre- 
pared to  assure  our  customers  that  no  fretting  will  ever  happen, 
as  they  are  never  exposed,  and  made  with  the  utmost  care. 

The  object-slide  should  not  be  oiled.  Never,  under  any 
condition,  use  emery  in  trying  to  repair  an  instrument,  as  it 
cannot  be  removed  again  and  will  grind  continually. 

An  efficient  lubricant  for  leveling  screws,  clamps,  pinions, 
etc.,  is  well  rendered  marrow. 

If  an  instrument  is  upset,  thereby  bending  centers  and 
plates,  do  not  turn  it  unnecessarily,  as  this  will  disfigure  the 
graduation,  but  send  it  to  a  competent  instrument  maker  im- 
mediately. There  should  be  no  delay  in  repairing  defects. 

In  the  matter  of  the  tripod,  it  is  wise  to  look  to  the  screws 
that  hold  the  legs  frequently,  and  to  keep  them  well  tightened 
up;  and  to  inspect  the  shoes,  to  see  that  they  do  not  come  loose. 
An  instrument  cannot  be  steady  if  there  is  any  shake  in  the 
tripod,  which  is  its  support  and  must  be  firm  in  every  particular. 

The  graduation  is  a  very  delicate  detail  to  handle,  and 
should  be  approached  only  with  the  utmost  care.  It  is  safe  to 
leave  this  part  to  the  instrument  maker,  and  not  to  attempt  to 
remove  the  plates,  as  they  cannot  be  properly  re-centered  with- 
out the  aid  of  a  testing  apparatus.  An  exposed  graduation 
may  be  cleaned  with  a  little  watch  oil  and  a  chamois  skin. 

To  preserve  the  sensitiveness  of  the  needle,  the  center  pin 
must  be  prevented  from  becoming  dull.  The  instrument  should 
never  be  lifted  without  raising  and  arresting  the  needle,  and  if, 
upon  letting  it  down  again,  the  swing  is  too  large,  gently  stop 
it  when  within  a  few  degrees  of  its  natural  bearing.  Every 
check  and  start  must  be  made  gently,  never  abruptly.  Should 


THE    A.     LIETZ    COMPANY.  55 

the  point  become  dull,  it  is  best  to  send  it  to  an  instrument 
maker;  if  this  be  not  practicable,  a  watchmaker  may  perhaps 
attend  to  it.  It  should  be  remembered,  however,  that  the  point 
of  poise  must  be  centered  —  that  is,  occupy  the  center  of  the 
graduated  circle.  This  cannot  be  done  by  a  watchmaker,  and 
is  only  to  be  relied  upon  if  made  in  an  instrument  maker's 
shop. 

If  a  needle  is  made  of  good  steel,  well  hardened  and  prop- 
erly charged,  it  will  not  often  lose  its  magnetism;  and  if,  when 
placed  away,  it  is  always  brought  to  lie  in  the  meridian,  it  will 
retain,  or  even  increase  its  polarity.  If  a  needle  has  lost  its 
magnetism  it  may  be  charged  again  with  an  ordinary  horse- 
shoe magnet;  one  of  three  inches  in  length  will  be  suitable  for 
this  purpose.  The  operation  is  this:  hold  the  magnet  with  the 
poles  upward,  then,  with  a  gentle  pressure,  pass  each  pole  of 
the  needle  from  center  to  extremity  over  the  opposite  pole  of 
the  magnet,  describing  before  each  pass  a  circle  with  a  diameter 
of  about  double  the  length  of  the  needle,  taking  care  not  to  re- 
turn it  in  a  path  near  the  pole.  If  the  magnet  is  strong  enough, 
the  needle  need  not  be  taken  out  at  all,  but  by  raising  it  against 
the  glass  and  then  passing  the  magnet  over  this,  it  will  be 
charged  sufficiently.  After  charging,  the  needle  has  lost  its 
balance,  which  may  be  easily  restored  by  shifting  the  brass  wire 
on  the  south  end. 

The  observer  should  always  satisfy  himself  that  there  be 
nothing  about  his  clothing,  especially  in  the  make  of  the  but- 
tons, that  would  have  any  influence  upon  the  needle. 

In  the  matter  of  the  telescope,  intelligent  handling  will  do 
much  towards  preserving  its  accuracy  and  reliability  for  a  long 
time.  In  cleaning  any  of  the  lenses,  use  a  soft  rag 'or  chamois 
leather.  If  the  glasses  should  become  greasy,  or  very  dirty, 
wash  them  with  alcohol.  The  inner  faces  will  seldom  require 
cleaning,  and  it  is  not  advisable  to  take  the  telescope  apart  too 
often,  as  it  is  likely  to  destroy  its  adjustment.  If  dust  should 
settle  on  the  cross-hairs,  it  is  safest  not  to  touch  them.  The 
only  remedy  that  may  be  tried  is  to  take  out  both  the  object- 
glass  and  the  eye-piece,  and  to  blow  gently  through  the  tube. 
This  may  remove  the  dust  without  injuring  the  threads,  but  it 
is  quite  a  delicate  operation. 


56  MODERN    SURVEYING    INSTRUMENTS. 

Cross-hairs  may  be  replaced  in  the  field  by  the  engineer. 
The  spider  web  is  cleansed  from  dirt  by  placing  it  in  water  for 
a  few  minutes.  A  little  manipulation  readily  removes  any 
particle  that  may  adhere  to  the  thread.  After  drying  for  a 
moment,  adjust  it  to  the  diaphragm,  previously  cleaned  from 
dust,  and  attach  it  by  means  of  a  little  shellac.  It  requires 
considerable  practice  to  do  this  nicely,  for  a  spider's  web,  al- 
though quite  strong,  cannot  be  handled  by  clumsy  fingers  with- 
out patting;  but  in  the  case  of  an  emergency  the  engineer  must 
try  to  do  the  best  under  all  circumstances. 

Referring  again  to  the  lenses,  it  is  well  to  remember  that 
in  taking  them  apart,  the  centering  is  disturbed,  and  the  engin- 
eer is  not  able  to  replace  them  properly,  especially  if  they  fit 
loosely  in  the  cell,  which  is  very  often  the  case.  The  staining 
of  flint-glass  lenses  is  caused  by  the  corrosion  of  the  oxide  of 
lead  contained  in  the  glass.  This  wrill  generally  occur  when 
the  lens  is  kept  in  a  damp  place  for  some  time.  In  cleaning 
an  object-glass,  care  should  be  taken  not  to  rub  it  any  more 
than  necessary.  Brush  off  the  dust  first  with  a  camel-hair 
brush,  and  then  wipe  it  carefully  with  a  clean  piece  of  chamois 
leather.  If  very  dirty,  wash  it  with  alcohol  or  water  and  soft 
chalk,  being  careful  to  have  the  latter  free  from  grit. 

Considering  that,  in  cleaning,  each  rub  will  destroy  more 
or  less  of  the  fine  finish  of  the  lens,  upon  which  depends  the 
brightness  and  brilliancy  of  the  image,  the  surveyor  will  be 
well  repaid  for  his  care  in  this  particular. 

Similar  attention  must  be  bestowed  upon  the  eye-piece. 
With  our  high  power  eye-pieces,  a  motion  of  only  three-six- 
teenths of  an  inch  is  necessary  to  allow  for  difference  in  eyes. 
As  the  sliding  motion  is  for  this  purpose  alone,  it  is  not  at  all 
necessary  to  disturb  it  after  it  has  once  been  properly  adjusted, 
as  long  as  the  same  person  is  using  the  instrument;  even  in 
packing  it  away  in  the  case  the  eye-piece  may  be  left  so,  as  this 
extra  extension  is  allowed  for  in  the  box.  The  cap  is  provided 
with  a  slide  to  protect  the  eye-lens  from  dust  while  the  instru- 
ment is  not  in  use;  the  engineer  should  never  neglect  to  close 
this,  and  to  cover  the  object-glass  with  its  cap  as  well,  as  soon 
as  the  instrument  is'set  at  rest. 


THE    A.    LIETZ    COMPANY.  57 

REPAIRS.* 

We  are  fully  piepared  to  make  careful  repairs  to  all  instru- 
ments, from  the  graduation  of  an  arc  or  circle,  and  the  straight- 
ening of  a  center  or  plate,  to  the  setting  of  a  simple  screw.  In 
this  particular  branch  we  have  operated  here  for  the  last  ten 
years,  and  have  gained  the  fullest  confidence  of  our  people. 
Attention  has  already  been  called  in  the  first  part  of  this 
Manual  to  the  first-class  facilities  that  we  have  for  making  re- 
pairs in  any  line — mechanical,  optical,  nautical  or  otherwise — 
and  for  that  reason  we  need  only  state  here  that  we  guarantee 
satisfaction  to  our  customers  in.  every  way. 

As  we  are  located  in  California,  separated  by  the  breadth 
of  the  Continent  from  our  Eastern  colleagues,  we  are  necessarily 
required  to  repair  instruments  of  almost  every  known  make, 
and  this  has  compelled  us  to  procure  the  various  requisites  in 
the  workshop,  for  all  emergencies.  To-day  we  are  in  the  posi- 
tion to  renew  any  part  of  an  instrument,  no  matter  where  it 
was  originally  manufactured.  Time  and  money  will  be  saved 
by  sending  directly  to  us,  and  we  shall  try  to  give  our  custom- 
ers every  satisfaction.  Whatever  is  entrusted  to  us  will  be 
thoroughly  overhauled,  and  put  in  the  best  possible  condition, 
unless  specified  orders  are  received  to  confine  the  repairs  to 
certain  details.  As  a  general  thing  it  ought  to  be  left  to  our 
judgment  as  to  what  the  instrument  requires;  it  may  cost  a 
little  more  if  you  follow  our  advice  in  this  particular,  but  it  will 
certainly  be  more  satisfactory  in  the  end.  It  will  save  time, 
trouble  and  additional  expense.  In  the  course  of  our  examina- 
tion of  an  instrument  needing  repairs,  we  discover  defects  that 
could  not  be  apparent  to  anyone,  before  its  parts  were  separated 
and  individually  tested.  What  may  appear  of  no  consequence, 
and  is  therefore  neglected,  is  quite  likely  to  lead  to  all  sorts  of 
subsequent  inaccuracies  in  your  work.  Years  of  experience  in 
this  particular  line  have  taught  us  the  advisability  of  urging 
this  point  upon  our  patrons. 

Considerable  correspondence  is  had  from  inquiries  about 
the  cost  of  repairs.  Although  it  is  impossible  to  state  the  exact 
figures  before  an  examination,  there  are  certain  rates  for  ordi- 
nary repairing  that  we  may  mention  here. 

*  Experience  has  taught  us  that  it  is  not  wise  to  allow  an  ordinary  mechanic  to  attempt 
instrumental  repairs,  as  frequently  resorted  to  in  inland  towns.  It  is  always  the  case  that 
this  proves  ruinous  to  the  instrument,  and  subsequent  repairs  will  be  more  extensive  and 
expensive  than  if  it  had  been  shipped  to  the  instrument-maker  at  once.  Express  charges 
are  cf  far  less  importance,  and  may  be  made  very  reasonable.  See  notice  preceding  preface 
to  this  manual. 


58  MODERN    SURVEYING    INSTRUMENTS. 

The  most  expensive  instrument  in  this  regard  is  the  transit, 
being  the  most  complicated  in  parts.  If  injured  by  a  fall,  new 
centers  and  a  new  telescope  axis  are  generally  required,  the  cost 
varying  from  $10  to  $30,  reaching  sometimes  as  high  as  $50. 
If  slightly  injured  it  will  vary  from  $5  to  $10. 

Injuries  sustained  by  leveling  instruments  are  generally 
less  serious.  A  new  level  vial  costs  from  $2  to  $7.50,  according 
to  size  and  sensitiveness.  Instruments  defective  in  construc- 
tion or  workmanship  will  not  require  a  sensitive  level,  as  that 
would  be  a  source  of  constant  annoyance  to  the  engineer;  the 
bubble  should  be  chosen  to  harmonize  with  the  general  qual- 
ities. As  a  rule,  we  attach  to  the  better  class  of  instrument  a 
level  that  shall  give  for  each  inch  of  motion  of  the  bubble  an 
angle  of  two  minutes;  to  the  inferior  grade,  one  of  three  or  four 
minutes. 

Compasses  sent  to  us  are  generally  injured  by  the  dulling 
of  the  center  pin.  Sometimes  the  plates  and  sights  are  bent 
and  the  glass  broken.  Often  the  center  cap  is  worn  out,  and  a 
new  one  is  required.  The  cost  of  repairing  ranges  from  $2  to 
$8,  and  even  as  high  as  $10.  A  new  needle,  having  the  largest 
breadth  in  a  vertical  direction,  which  is  far  superior  to  the  flat 
style,  costs  $5.  A  new  center  pin,  75  cents.  New  center  cap 
with  jewel,  $1.50. 

Careful  re-adjustments  made  under  the  collimators  are 
charged  for  at  the  rate  of  $2.50  for  each  instrument. 

Transits  and  levels  should  always  be  accompanied  by  the 
leveling  plates;  the  tripod  and  head  need  not  be  sent.  With 
compasses  the  ball  spindle  should  be  sent. 

We  advise  our  customers  to  pack  their  instruments  care- 
fully, when  sending  them  to  us  for  repairs,  as  they  are  liable  to 
material  injury  if  this  precaution  be  neglected.  The  space  in 
the  box  between  the  different  parts  —  of  the  transit  particu- 
larly—  may  be  filled  with  soft  paper  wads  to  protect  it  from 
jars  and  blows.  It  is  well  to  put  the  case  in  an  additional  box, 
a  little  larger  in  dimensions,  in  such  a  manner  that  the  top  of 
the  case  is  plainly  visible  and  its  leather  strap  handy  for  carry- 
ing. The  space  between  the  case  and  the  box  may  be  padded 


THE    A.    LIETZ    COMPANY.  59 

with  shavings,  or   some  soft  material  to  take   up   the  shocks. 
Mark  upon  the  top  of  the  box  in  large  legible  letters: 


THIS  SIDE  UP  !  I  ! 
SCIENTIFIC     INSTRUMENT, 
HANDLE  WITH  CARE!! 


And  ship  through  a  responsible  express  company,  plainly  ad- 
dressed to: 

THE     A.     LIETZ     CO., 

422  SACRAMENTO  STREET, 

San  Francisco,  Cal. 

The  name  of  the  sender  and  his  address,  together  with  the  value 
of  the  instrument,  should  also  appear  on  the  box. 

This  will  insure  comparative  safety  in  transportation,  which 
is  a  point  that  should  be  well  observed  by  the  engineer.  And 
this  precaution  would  also  increase  the  responsibility  of  the 
carrier,  in  case  the  instrument  had  suffered  during  transporta- 
tion. 

When  an  instrument  is  sent;  to  us  for  repairs,  a  letter  or 
postal  card  should  be  mailed  at  the  same  time,  to  inform  us  of 
the  fact,  giving  the  necessary  directions,  and  stating  when  the 
return  is  required.  The  receipt  of  the  instrument  will  be  ac- 
knowledged by  us  at  once. 

ADJUSTMENTS. 

Adjusting  an  instrument  consists  in  delicately  moving  to 
the  right  or  left,  and  up  or  down,  certain  parts  that  must  be 
either  parallel  or  at  right-angles  to  each  other.  This  is  done 
by  slightly  turning  a  number  of  capstan-headed  screws  or  nuts 
by  means  of  a  small  steel  rod,  called  an  adjusting  pin.  Adjust- 
ing the  vernier  and  compass  consists  in  placing  certain  points 
in  a  straight  line;  but  as  these  corrections  are  always  made  by 
the  instrument  maker,  they,  do  not  properly  apply  to  the  sub- 
ject before  us.  Verniers,  limb  and  needle,  if  properly  placed  at 
the  outstart,  will  not  need  any  correction  in  the  ordinary  use. 


60  MODERN    SURVEYING    INSTRUMENTS. 

Of  the  Transit. 

1.  ADJUSTMENT  FOR  PARALLAX. — This  is  a  very  essential 
one,  and  must  be  looked  to  carefully  in  every  surveying  instru- 
ment, whether  transit,  level  or  theodolite.     It  consists   in  so 
focusing  the  eye-piece,  that  the  cross-hairs  shall  stand  out  dis- 
tinctly and  well-defined,  when  the  telescope  is  directed  upon  an 
object  in  focus.     If  this  is  not  properly  done  the  hairs  will  be 
dim;  they  will  appear  to  travel  and  to  seem  unsteady  when  set 
on  a  mark.     We  know  that  this  has  given  considerable  vexation 
to  the  observer,  and  instruments  have  been  disparagingly  con- 
demned for  their  apparent  parallax,  when  nothing  more  was 
necessary  than  a  slight  movement  of  the  eye-tube  to  focus  the 
hairs  properly.     This  fact  should  be  well  borne  in  mind.     Our 
eye-pieces  are  quite  easily  moved  in.  or  out  by  a  revolving  mo- 
tion, which  affords  a  very  fine  and  precise  adjustment  to  focus. 

Operation. — Direct  the  telescope  so  as  to  have  a  clear  view 
of  the  sky,  and  then  turn  the  eye-tube  by  the  cap  as  just  de- 
scribed, until  the  cross-hairs  stand  out  like  two  sharp  and  dis- 
tinctly drawn  black  lines.  After  a  few  trials  this  is  accomplished 
without  difficulty.  Then  try  the  telescope  upon  some  object 
brought  into  focus  and  test  the  clearness  of  the  wires.  A  point 
now  bisected  must  stay  so  wliile  the  eye  is  moved  laterally  in 
front  of  the  eye-hole.  If  it  remain  stationary,  there  is  no  par- 
allax and  the  adjustment  is  made.  Once  properly  set,  the  eye- 
piece may  remain  for  the  same  observer  for  all  time,  and  need 
not  be  adjusted  from  day  to  day.  Attention  has  already  been 
called  to  this  point  in  a  previous  chapter,  where  it  was  noted 
that  the  instrument  box  was.  made  large  enough  to  allow  the 
eye-piece  to  extend  beyond  the  tube.  (The  sun-shade  should 
be  put  on  the  telescope  first,  and  then  focused  to  mean  distance 
to  balance  it  properly.) 

2.  PLATE  LEVELS. — The  object  is  to  set  the  levels  at  right- 
angles  to  the  vertical  axis  of  the  instrument,  so  that  when  the 
bubbles  are  centered  the  axis  is  truly  vertical. 

Operation. — Bring  the  bubbles  to  the  middle  of  the  tube  by 
means  of  the  leveling  screws,  then  turn  the  instrument  on  its 


THE    A.     LIETZ    COMPANY.  61 

center  180  degrees.  If  they  remain  central  for  any  position, 
they  are  in  adjustment;  if  not,  they  must  be  elevated  or  de- 
pressed at  one  end  to  correct  them.  One-half  of  the  required 
correction  is  made  with  the  capstan-headed  screws  on  the  vial 
case,  the  rest  by  the  leveling  screws  of  the  instrument.  Several 
repetitions  of  the  operation  may  be  required  before  attaining 
accuracy.  It  is  well  to  have  the  plate  in  such  a  position,  that 
the  levels  shall  be  parallel  to  a  pair  of  opposing  foot  screws.  If 
they  are  out  considerably,  it  is  better  to  adjust  one  first,  approx- 
imately, and  then  the  other. 

3.  THE  STANDARD  BEARINGS. — The  telescope  should  re- 
volve in  a  vertical  plane  when  the  instrument  is  level.  One 
end  of  the  telescope  axis  must  be  either  raised  or  lowered  until 
accuracy  is  reached.  A  capstan-headed  screw  is  attached  for 
that  purpose. 

Operation. — Set  the  instrument  up  within  about  fifty  feet 
of  the  wall  of  a  house.  Take  a  well-defined  point  as  high  up 
as  possible  on  the  wall;  clamp  and  bisect;  then  turn  down  the 
telescope  and  put  a  point  in  line  as  low  on  the  wall  as  may  be 
conveniently  reached.  Reverse  the  telescope  and  direct  again 
to  the  upper  mark,  if  you  please;  clamp  and  bisect;  turn  down 
to  the  lower  mark,  and  if  it  is  bisected,  the  telescope  revolves 
in  a  vertical  plane  and  requires  no  adjustment.  If  it  does  not 
strike  the  point  absolutely,  one-half  of  the  difference  is  taken 
up  by  the  capstan-headed  screw,  and  the  adjustment  is  done. 
Several  repetitions  of  the  operation  may  be  required.  It  is  not 
necessary  to  level  the  instrument,  but  it  should  be  brought  in 
such  a  position  as  to  admit  the  bisecting  of  two  well-defined 
points.  Care  should  be  taken,  however,  that  the  observation  is 
made  at  the  intersection  of  the  cross-wires,  and  that  the  instru- 
ment is  securely  clamped. 

This  adjustment  should  always  be  made  before  that  of  the 
cross-wires,  for  this  r.eason:  that  unless  points  of  equal  height 
are  taken  in  the  subsequent  adjustment  of  the  vertical  hair,  it 
will  only  then  prove  correct,  if  the  telescope  revolve  in  a  truly 
vertical  plane.  It  is,  therefore,  always  better  to  look  to  this 
before  the  cross-hairs  are  adjusted. 


62  MODERN    SURVEYING    INSTRUMENTS. 

This  adjustment  may  also  be  made  by  means  of  an  accurate 
striding  level,  such  as  manufactured  by  this  Company  for  use 
in  high-grade  instruments.  The  transit  must  be  precisely  lev- 
eled up  by  the  foot-screws  and  plate  bubbles,  after  which  the 
striding  level  is  placed  across  the  telescope,  resting  upon  its 
axis.  It  is  evident  that  the  bubble  will  indicate  any  deficiency 
in  the  horizontal  parallelism  of  this  axis,  and,  therefore,  any 
error  in  the  true  vertical  motion  of  the  telescope,  which  may  be 
corrected  until  the  bubble  of  the  striding  level  remains  centered. 

4.  THE  CROSS-WIRES.— The  line  of  collimation  should  be 
at  right-angles  to  the  axis  upon  which  the  telescope  revolves. 

Assuming  that  all  the  required  conditions  have  been  ful- 
filled by  the  instrument  maker — having  placed  the  telescope  in 
the  center  of  the  instrument,  and  having  the  tubes  perfectly 
straight  and  normal  to.  the  telescope  axis,  which  are  necessary 
instrumental  requirements,  there  are  two  methods  that  may  be 
employed.  One  is  by  means  of  back-  and  fore-sights,  which  is 
that  generally  used;  the  other  consists  of  a  test  by  means  of 
three  points  in  a  range,  where  the  middle  one  is  occupied. 
Preceding  either  method  the  hair  should  be  made  truly  vertical, 
so  that  either  the  upper  or  lower  end  will  bisect  a  point  when 
the  telescope  is  moved  up  and  down.  This  is  easily  done  by 
loosening  the  diaphragm  and  turning  it  slightly  in  the  required 
direction.  To  accomplish  this  the  instrument  must  be  leveled 
up. 

Operation,  First  Method. — Occupying  a  point,  direct  the 
telescope  to  some  well-defined  mark,  about  four  hundred  or  five 
hundred  feet  distant;  clamp  and  bisect  it;  then  revolve  the  tel- 
escope and  place  a  point  in  the  opposite  direction  at  about  the 
same  distance.  Now  unclamp  and  turn  the  instrument  half- 
way around;  set  the  hair  again  on  the  first  point,  revolve  the 
telescope  and  sight  to  the  second  point.  If  the  intersection  bi- 
sects the  latter,  the  vertical  hair  is  in  adjustment.  If  not,  the 
error  can  be  corrected  by  the  capstan-headed  screws,  which 
afford  a  lateral  motion  of  the  diaphragm.  With  them  the  ver- 
tical thread  should  be  moved  one-fourth  of  the  space  intercepted 
between  the  direction  of  the  telescope  and  the  direction  of  the 


THE    A.     LIETZ    COMPANY.  gg 

second  point.  Several  repetitions  may  be  necessary  to  obtain 
accuracy. 

The  reason  why  only  one-fourth  of  the  space  should  be 
corrected  for,  becomes  evident  from  the  fact,  that  in  the  first 
revolution  of  the  telescope  the  error  of  the  hair  is  doubled;  and 
after  reversing  the  instrument  and  revolving  the  second  time, 
it  is  again  doubled,  but  on  the  opposite  side,  so  that  the  true 
direction  lies  exactly  half  way  between  the  two,  and  to  correct 
for  it  we  must  move  the  hair  one-half  the  space  between  the 
true  line  and  one  of  the  points. 

It  is  not  necessary  to  level  the  instrument  in  order  to  make 
this  adjustment;  but  in  case  it  is  not  leveled  up,  the  observa- 
tions must  be  made  exactly  at  the  intersection  of  the  cross-wires. 

It  must  be  remembered  that  the  image  at  the  cross-hairs  is 
inverted,  and  that  in  consequence  the  screws  must  be  moved  in 
apparently  wrong  directions. 

If  there  is  any  lost  motion  in  the  tangent  screw,  great  care 
should  be  exercised  in  handling  the  telescope,  so  as  not  to  in- 
fluence its  alignment. 

Operation,  Second  Method. — Locate  with  the  telescope  three 
points  in  one  direction,  which  are  necessarily  in  a  straight 
line,  as  long  as  the  vertical  movement  of  the  telescope  is  in  ad- 
justment. Occupy  the  middle  point  with  precision,  and  bisect 
one  of  the  end  points;  revolve  the  telescope  and  sight  at  the 
other  end  point.  If  this  is  bisected,  the  instrument  is  in  ad- 
justment; if  not,  correct  for  it  by  taking  up  one-half  the  error. 
This  method  requires  leveling  of  the  instrument. 

Thus  far  we  have  been  speaking  of  the  vertical  hair  only, 
as  it  is  the  more  important  in  a  transit  telescope.  In  a  plain 
transit  —  that  is,  one  without  a  telescope  level  and  without  a 
vertical  arc  —  the  horizontal  thread  simply  serves  to  define  the 
middle  of  the  vertical  one,  so  that  the  observation  may  always 
be  confined  to  a  particular  point  in  the  latter.  But  if  a  level  is 
attached  to  the  telescope,  then  the  horizontal  hair  should  be 
brought  into  the  optical  axis,  before  the  level  is  set  parallel  to 
the  line  of  collimation;  otherwise,  though  adjusted  for  long 
distances,  it  will  fail  to  be  correct  for  short  sights. 


64  MODERN    SURVEYING    INSTRUMENTS. 

Operation.  —  Set  up  the  instrument  near  a  house  or  fence 
and  level  up  carefully.  Clamp  the  telescope,  and  by  means  of 
its  tangent  screw  bisect  a  point  several  hundred  feet  distant; 
then  turn  on  center  and  mark  a  point  on  the  house  or  fence, 
.about  ten  feet  distant.  Now  unclamp  telescope,  reverse  it,  re- 
volve on  center,  and  again  bisect  the  nearest  point.  Turn 
instrument  on  center  and  see  whether  the  hair  intersects  the 
further  point.  If  it  does  not,  the  correction  must  be  made,  by 
lifting  or  lowering  the  diaphragm  by  means  of  the  upper  and 
lower  capstan-headed  screws,  until  the  bisections,  after  repeated 
trials,  will  coincide. 

5.  THE  TELESCOPE  LEVEL. — The  object  of  this  adjust- 
ment is  to  make  the  level  parallel  with  the  line  of  collimation. 
The  principle  underlying  the  method  is:  that  points  taken  with 
the  same  angle  of  elevation  or  depression,  and  equally  distant 
from  the  instrument,  are  of  equal  height. 

Operation. — Set  up  on  a  nearly  flat  surface  and  level  care- 
fully. On  opposite  sides,  at  equal  distances,  drive  two  stakes 
giving  the  same  level-rod  reading,  with  the  telescope  bubble 
centered  in  each  instance.  These  points  are  necessarily  on  a 
level  with  each  other.  Now  move  the  instrument  to  a  point  in 
line  with  both,  and  about  ten  feet  distant  from  one.  Level  up 
again.  Take  a  rod  reading  on  the  nearer  and  then  on  the 
further  stake.  If  they  agree,  the  level  is  in  adjustment;  if  not, 
move  the  telescope  with  its  tangent  screw  over  nearly  the  whole 
error,  and  sight  again  at  the  nearer  stake  and  then  at  the 
further,  repeating  this  until  the  readings  are  the  same  on  both, 
when  the  telescope  is  truly  horizontal.  Now  bring  the  bubble 
in  the  center  of  the  tube  by  the  correcting  screws  of  the  level, 
and  the  adjustment  is  completed. 

This  adjustment  may  also  be  made  in  a  room  with  the  aid  of 
a  surveyor's  level,  with  absolute  accuracy. 

Operation. — A  few  feet  (one  or  more)  from  each  other  set 
up  the  transit  and  level,  each  directed  to  the  other.  The  cross- 
hairs of  the  level  must  be  illuminated  by  a  light,  so  that  they 
shall  become  plainly  and  clearly  visible  through  the  transit. 
For  this  purpose  cover  the  eye-end  of  the  level  with  a  bit  of 


.  THE    A.     LIETZ    COMPANY.  55 

wnite  paper  and  place  a  lamp  behind  it.  Focusing  both  in- 
struments properly  will  make  the  hairs  appear  very  distinctly. 
Now,  if  both  instruments  are  properly  collimated,  the  level 
carefully  leveled  up,  and  the  transit  telescope  of  such  height 
that  we  may  view  the  interior  of  the  level's  tube,  we  are  ready 
to  adjust  the  transit  telescope  to  a  level  plane,  which  is  done 
by  simply  placing  the  intersection  of  its  cross-hairs  delicately 
over  the  intersection  of  the  level's  cross-hairs.  All  that  is  re- 
quired after  that,  is  to  center  the  transit's  level  bubble  by  means 
of  the  proper  adjusting  screws. 

This  method  recommends  itself  on  account  of  its  extreme 
simplicity. 

6.  ZERO  OF  VERTICAL  ARC. — This  adjustment,  once  made 
by  the  instrument  maker,  is  seldom  vitiated.     The  object  is  to 
have  the  zero  line  of  the  circle  agree  with  the  zero  mark  of  its 
vernier,  when  the  level  of  the  telescope  indicates  a  horizontal 
position,  and  when  the  centers    of    the   instrument  are  truly 
vertical. 

Operation.- — The  instrument  must  be  carefully  leveled  by 
the  small  plate  bubbles,  and  then  the  telescope  by  means  of  its 
level.  This  accurately  accomplished,  the  vernier  is  shifted 
until  the  zero  lines  coincide.  This  must  be  carefully  done,  so 
that  the  instrument  is  not  disturbed,  and,  when  the  vernier  is 
fastened,  care  must  be  taken  to  allow  a  space  that  shall  neither 
be  too  small  nor  too  great  between  it  and  the  vertical  circle. 
In  the  first  case  it  would  bind  under  certain  conditions  of  tem- 
perature, and  in  the  latter  the  observer  would  not  be  able  to 
obtain  an  accurate  reading.  The  coincidence  of  the  zero-lines 
must  be  made  with  a  magnifying  glass,  and  all  parallax  avoided. 

7.  CENTERING  THE    FIELD    OF   VIEW. —  On    some    transit 
telescopes  there  will    be  found   another  set   of    four   capstan- 
headed  screws,  exactly  alike  to  that  which  regulates  the  cross- 
hair diaphragm,  and   placed  in  a   position  quite   close   to   it. 
These  screws  are    for   the    purpose    of    directing   the    tube   of 
the  eye -piece  in  such  a  manner  that  the    field  of  view  may 
foe  divided  by  the  cross -wires   into   four  uniform  quadrants; 
that  is,  they  enable  the  operator  to  so  adjust  his  field  that  it  may 


66  MODERN    SURVEYING    INSTRUMENTS, 

be  bisected  horizontally  and  vertically  by  the  threads.  In  the 
Lietz  transits  this  adjustment  has  been  omitted,  for  the  reason 
that  the  tubes  are  made  of  such  length  and  with  such  care  — 
being  absolutely  straight — that  there  is  no  need  of  displacing 
the  field,  after  the  line  of  collimation  has  been  made  to  agree 
with  the  optical  center,  and  the  hairs  are  properly  adjusted. 
The  lines  can  never  appear  noticeably  out  of  the  field  in  our 
transits,  and  any  additional  movement  in  the  parts  of  the  tel- 
scope  would  neither  be  useful  nor  desirable.  A  first-class  transit 
instrument  can  dispense  with  this  arrangement  altogether,  and 
for  this  reason  it  is  not  usually  found  there.  With  an  extra 
long  telescope,  however,  there  would  be  a  slight  advantage  in 
being  able  to  direct  the  field  of  view,  for  a  possible  fall  of  the 
instrument  may  so  injure  the  tube  that  it  could  not  be  made 
absolutely  straight  again  afterwards,  and  in  consideration  of 
this,  we  have  adopted  this  correction  only  in  the  case  of  the 
18-inch  Y-level,  which  is  the  most  liable  to  be  damaged  in  that 
way.  It  alone  possesses  two  sets  of  capstan-headed  screws  near 
the  eye-end  of  the  telescope  —  one  for  the  adjustment  of  the 
cross-hairs,  and  the  other  for  shifting  the  field  of  view  so  that 
it  shall  appear  equally  divided  by  them. 

Of  the  Y- Level. 

There  are  three  principal  adjustments.  The  spirit  level 
must  be  parallel  to  the  axis  of  collimation;  it  must  be  at  right- 
angles  to  the  vertical  axis  of  the  instrument;  the  axis  of  colli- 
mation must  agree  with  the  optical  axis. 

There  are  other  instrumental  requirements  which  belong 
to  the  instrument  maker,  however,  and  it  is  with  the  above 
three  adjustments  only  that  the  surveyor  has  to  deal,  as  they 
are  likely  to  become  disturbed  in  time. 

Before  examining  the  adjustments,  the  sun-shade  should  be 
placed  on  the  telescope,  as  it  is  only  accurately  in  balance  with 
this. 

IST  ADJUSTMENT. — To  set  the  spirit  level  parallel  to  the  line 
of  collimation,  and,  at  the  same  time,  place  its  axis  in.  a  plane 
with  that  of  the  telescope.  It  is  best  to  attend  to  the  latter  first. 

Operation. — Turn  the  telescope  so  as  to  stand  over  two  op- 


THE    A.     LIETZ    COMPANY.  67 

posing  foot-screws,  clamp  the  instrument  and  bring  the  bubble 
to  the  center  of  the  tube;  then  rotate  the  telescope  in  its  Ys,  so 
as  to  put  the  level  considerably  out  of  a  vertical — say  about  15 
or  20  degrees.  If  the  bubble  changes  its  position,  it  shows 
that  the  axis  is  not  in  a  plane  with  that  of  the  telescope.  Cor- 
rect it  by  moving  the  two  side  screws  of  the  level  case,  until 
one-half  of  the  deviation  has  been  taken  up.  A  few  repetitions 
will  insure  accuracy,  and  destroy  the  side  motion  of  the  level. 

The  level  must  now  be  made  parallel  with  the  line  of  the 
bottom  of  the  collars. 

Operation. — Bring  the  bubble  to  the  center  of  the  tube; 
then  reverse  the  telescope  in  the  Ys  end  for  end;  do  this  care- 
fully. The  displacement  of  the  bubble,  if  there  be  any,  is  the 
double  error,  which  is  corrected  by  taking  up  one-half  of  it  by 
means  of  the  adjusting  nuts  on  the  level  case,  and  the  other 
half  with  the  leveling  screws  of  the  instrument.  This  opera- 
tion is  repeated  until  the  bubble  remains  in  the  center. 

To  accomplish  a  proper  adjustment  of  the  level  to  the  line 
of  collimation,  it  becomes  absolutely  necessary  that  the  collars 
be  of  equal  diameter.  We  have  already  referred  to  the  import- 
ance of  even  collar  dimensions,  and  have  laid  great  weight  upon 
this  requisite;  and  here  again  we  shall  point  out  the  errors  to 
which  a  neglect  therein  may  lead.  A  Y- level  in  such  an  event 
is  not  any  better  than  a  dumpy,  and  will  have  to  be  adjusted  as 
such. 

Providing  the  Ys  are  filed  out  to  the  same  absolute  angle, 
the  instrument  may  still  be  adjustable  in  all  its  parts: — the 
spirit  level  may  be  made  parallel  to  the  line  of  the  bottom  of 
the  collars;  the  Ys  may  be  so  adjusted  that  the  bubble  will  re- 
main in  the  center  of  the  tube;  the  line  of  collimation  may  be 
brought  to  the  center  of  revolution  of  the  telescope;  and  this 
reversed  end  for  end  in  the  Ys,  leaving  the  bubble  in  the  mid- 
dle, even  if  there  be  some  difference  in  the  diameter  of  the 
collars.  It  is  the  general  opinion  that  after  level,  Ys  and  cross- 
wires  are  adjusted,  the 'instrument  must  be  correct.  This  is  by 
no  means  certain,  as  the  least  difference  in  the  size  of  the  col- 
lars will  throw  out  the  line  of  collimation  considerably.  This 
difference  is  sometimes  found  in  new  instruments,  and  is  also 


(58  MODERN  SURVEYING  INSTRUMENTS. 

produced  by  unequal  wear,  denting,  etc.  It  is  therefore  ad- 
visable that  the  equality  of  the  collars  should  be  tested  from 
time  to  time,  which  is  done  by  a  method  given  further  on. 

2o  ADJUSTMENT. — To  place  the  level  at  right-angles  to  the 
vertical  axis  of  the  instrument. 

Operation. — Turn  the  instrument  so  that  the  telescope  shall 
stand  over  the  line  of  two  opposing  leveling  screws,  and  bring 
the  bubble  to  the  center  of  the  tube;  then  turn  the  instrument 
180  degrees  on  its  center.  If  the  bubble  shows  any  displace- 
ment, correct  one-half  of  it  by  means  of  the  nuts  under  the 
bar  at  the  Y  supports,  and  one-half  by  the  foot-screws.  Several 
trials  will  make  the  correction  perfect. 

SD  ADJUSTMENT. — To  place  the  cross-web  in  the  optical 
axis  of  the  telescope,  so  that  the  intersection  will  remain  on  an 
object  in  revolving  it. 

Operation. — Set  the  intersection  of  the  hairs  on  a  point 
about  two  hundred  or  three  hundred  feet  distant,  then  revolve 
the  telescope  in  its  Ys  half-way,  so  as  to  have  the  level  case  on 
top.  If  the  wires  have  moved  from  the  point,  bring  them  back 
one-half  of  the  amount  of  the  displacement.  Try  again,  and 
repeat  the  operation  if  necessary. 

The  eye-piece  may  then  be  properly  aligned  and  directed 
by  the  four  black  capstan-headed  screws  (nearest  the  eye-end  of 
the  telescope),  so  that  the  field  of  view  shall  appear  evenly  di- 
vided by  the  cross-hairs,  as  already  explained. 

In  this,  as  well  as  in  any  other  telescope,  we  assume  that 
the  tubes  are  straight,  the  object-glass  well  centered,  and  the 
slide  well  fitted.  If  such  be  not  the  case,  the  telescope  can  only 
be  adjusted  for  certain  distances.  It  is  urged  by  some  makers 
that  it  is  almost  impossible  to  produce  straight  tubes,  and  that, 
therefore,  the  object-slide  must  be  adjustable.  This,  however, 
is  entirely  erroneous.  Perfectly  straight  tubes  can  be  made,  if 
the  necessary  time  and  money  be  expended,  which  is  the  only 
requisite.  In  a  great  many  instruments  sold  to-day,  you  will 
find  that  the  object-glass  is  not  centered,  that  the  slide  is  poorly 
fitted,  and  that  all  these  inaccuracies,  which  are  not  apparent 
at  a  glance,  prove  more  injurious  than  ever  if  the  tubes  are  not 


THE    A.     LIETZ    COMPANY.  gg 

quite  straight.  It  must  also  seem  clear  to  any  one,  that  the 
constant  working  of  the  slide  in  an  adjustable  ring  would  loosen 
the  screws  and  cause  considerable  annoyance. 

PARALLAX  is  adjusted  by  moving  the  eye-piece  in  or  out 
until  a  clear  and  distinct  view  of  the  cross-hairs  is  obtained,  as 
in  the  case  of  the  transit  already  described. 

THE  COLLAR  TEST.  —  After  the  instrument  is  properly  ad- 
justed, the  equality  of  the  collars  may  be  ascertained  in  the 
followin  manner: 


Operation.  —  Make  two  bench-marks,  place  the  instrument 
exactly  midway  between  them,  and  find  their  true  difference  of 
level  by  reading  leveling  rods  set  upon  them.  Now  place  the 
instrument  near  one  of  the  bench-marks  and  read  the  rods 
again.  If  the  difference  of  the  readings  is  equal  to  the  true 
difference  of  level,  the  collars  are  of  equal  diameter,  and  the 
line  of  collimation  is  at  right-angles  to  the  vertical  axis  of  the 
instrument.  This  test,  once  made,  holds  good  ever  after,  as  it 
shows  that  the  collars  are  true,  and  consequently  that  a  correct 
adjustment  is  assured  of  all  its  other  parts,  as  already  described. 
But  it  need  hardly  be  mentioned  that  denting,  the  settling  of 
sand  particles  and  unequal  wear  will  also  affect  the  adjustment 
in  the  same  manner. 

If  the  test  shows  that  the  line  of  collimation  is  not  perpen- 
dicular to  the  line  of  the  -vertical  center,  then  the  collars  are  of 
unequal  diameter,  and  the  instrument  is  really  nothing  more  or 
less  than  a  dumpy  level,  as  this  defect  deprives  it  of  all  the  ad- 
vantages for  an  easy  and  convenient  adjustment,  which  charac- 
terizes the  Y-  level  in  comparison  with  the  dumpy. 

This  defect  may,  however,  be  temporarily  remedied  or 
adjusted  in  the  same  manner  as  the  line  of  collimation  in  the 
dumpy  level  is  adjusted,  but  it  must  ever  thereafter  remain 
permanently  in  its  Ys,  as  it  would,  if  reversed  end  for  end, 
double  the  error  which  existed  previous  to  this  adjustment. 

The  correction  may  also  be  made  by  displacing  the  hori- 
zontal cross-hair  to  the  extent  that  the  line  of  collimation  shall 
be  truly  horizontal  and,  at  the  same  time,  parallel  with  the  axis 
of  the  spirit  level;  but,  in  that  event,  there  will  be  no  longer 


70  MODERN    SURVEYING    INSTRUMENTS, 

any  agreement  with  the  optical  axis,  which  again  gives  rise  to 
a  number  of  inaccuracies  that  cannot  be  obviated. 

A  Y- level,  in  order  to  deserve  that  name  at  all,  must  have 
equal  diameters  of  its  collars;  and  if  that  is  not  found  after  a 
crucial  test,  the  instrument  maker  should  be  called  upon  to 
remedy  this  discrepancy. 

No  doubt  can  possibly  exist  in  the  mind  of  any  engineer 
of  the  absolute  necessity  of  the  collar  test.  Considering  the 
required  parallelism  of  the  axis  of  collimation  and  the  axis 
of  the  spirit  level,  he  must  know  that  a  contact  can  only  be  made 
between  telescope  and  Ys  by  means  of  the  collars,  whose  ex- 
teriors may  either  be  parts  of  the  surface  of  a  cylinder,  or  that 
of  a  cone,  and  that  the  required  parallelism  is  only  possible  in 
the  former  case.  If  one  collar  exceed  the  other  in  diameter, 
the  centered  level  bubble,  if  reversed  in  the  Ys,  will  indicate  a 
displacement  corresponding  to  four  times  the  angle  intercepted 
between  the  collar  axis  and  that  of  the  spirit  level.  No  further 
demonstration  of  this  fact  is  necessary. 

Of  the  Dumpy  Level. 

In  principle,  the  same  laws  govern  the  requirements  of  the 
dumpy  that  hold  good  in.  the  Y- level.  Although  its  construc- 
tion differs,  the  condition  of  its  line  of  collimation,  optical 
center  and  level  vial  must  be  such  as  to  bear  that  universal  re- 
lation to  each  other,  which  we  have  fully  explained  in  the  other 
instruments.  It  is  not  difficult  to  make  all  the  necessary  ad- 
justments properly,  although  it  may  not  appear  quite  so  handy 
to  correct  its  errors  as  in  the  case  of  the  Y-  level.  Once  ad- 
justed, however,  the  instrument  will  remain  so  for  a  long  time, 
and  it  will  give  the  operator  considerable  satisfaction,  if  used 
with  the  ordinary  care. 

The  adjustments  of  the  level,  and  the  telescope  for  collima- 
tion, will  now  be  briefly  mentioned. 

Put  on  the  sun-shade,  and  focus  the  eye-piece  until  the 
hairs  are  distinctly  visible  and  the  parallax  destroyed;  then 
proceed  as  follows: 

Operation. — Turn  the  instrument  so  that  the  telescope  shall 
stand  directly  over  the  line  of  two  opposing  leveling  screws, 


THE    A.     LIETZ    COMPANY.  71 

and  draw  the  bubble  to  the  middle  of  the  tube  by  means  of  the 
foot-screws.  Then  turn  the  instrument  on  its  center  180  de- 
grees, and  if  the  bubble  remain  centered  the  adjustment  is 
perfect.  Any  displacement,  however,  will  have  to  be  corrected 
by  taking  up  one-half  of  it  with  the  capstan-headed  screws  at- 
tached to  the  level  case,  and  the  other  half  by  the  foot-screws. 
This  operation  must  be  repeated  several  times,  in  directions 
normal  to  each  other  —  that  is,  over  one  set  of  opposing  foot- 
screws  as  well  as  over  the  other,  until  the  telescope  may  be 
swung  in  any  position  and  the  bubble  will  remain  in  the  mid- 
dle. See  that  the  adjusting  screws  of  the  level  vial  are  firm,  yet 
avoid  all  unnecessary  force  in  tightening  them;  all  cramming 
is  injurious,  and  tends  to  destroy  the  proper  degree  of  refine- 
ment required. 

After  having  set  the  diaphragm  so  that  the  cross-hairs  shall 
be  absolutely  horizontal  and  vertical,  which  is  easily  done  by 
loosening  the  capstan-headed  screws  and  turning  the  diaphragm 
slightly,  being  guided  by  some  point  bisected  by  the  horizontal 
hair,  we  now  proceed  to  adjust  the  cross-hair,  which  must  be 
brought  into  the  collimation  line.  Several  methods  are  known; 
the  one  which  is  always  available,  however,  is  that  by  means  of 
stakes  and  level-readings  upon  them,  and  it  is  to  this  that  we 
shall  confine  ourselves  here. 

Operation. — Choose  a  piece  of  ground  nearly  level,  set  up 
the  instrument  and  center  the  bubble.  Drive  a  stake  (point  1) 
firmly,  say  two  hundred  or  three  hundred  feet  from  the  instru- 
ment, in  any  convenient  direction  therefrom.  Hold  the  level 
rod  upon  it  and  take  a  reading.  Now  point  the  telescope  in  the 
opposite  direction,  the  bubble  being  centered,  and  plant  another 
stake  (point  2)  at  the -same  distance  from  the  dumpy,  driving  it 
until  the  rod  shall  read  the  same  as  upon  the  first  point.  These 
two  stakes  are  on  the  same  level.  Now  set  up  the  instrument 
about  ten  or  fifteen  feet  from  the  first  stake,  and  bring  the 
bubble  to  the  center;  take  a  rod-reading  on  point  1,  and  then 
on  point  2.  If  the  two  readings  are  alike  with  a  truly  centered 
bubble,  the  hair  is  collimated.  If  there  is  any  difference,  take 
up  nearly  all  of  it,  by  moving  the  diaphragm  with  the  cross- 
hairs either  up  or  down,  as  already  explained.  Repeat  this 


72  MODERN    SURVEYING    INSTRUMENTS, 

operation  until  the  readings  on  points  1  and  2  are  identical, 
when  the  instrument  is  in  adjustment. 

The  vertical  hair  is  of  no  particular  importance. 

With  these  precautions,  a  dumpy  level  may  be  made  abso- 
lutely accurate,  and  there  is  no  reason  why,  for  any  of  the  land 
surveyors,  and  for  nearly  all  of  the  engineer's  work,  this  com- 
pact and  steady  instrument  should  not  meet  every  requirement. 
We  frequently  discuss  its  merits  with  our  customers,  and  have 
never  hesitated  to  recommend  it. 

Test  of  Telescopes  in  General. 


If  a  telescope  is  to  be  tested  for  its  qualities,  make  sure 
that  all  its  lenses  are  perfectly  clean. 

To  test  for  definition,  use  small,  clear  print,  and  view  it 
from  a  distance  of  from  thirty  to  fifty  feet.  If  the  print  ap- 
pears clear  and  well  defined,  and  fully  as  legible  at  this  distance 
as  if  viewed  with  the  naked  eye  at  the  distance  of  distinct 
vision,  the  surfaces  of  the  object-glass  are  perfect  and  well  fin- 
ished. If,  on  the  contrary,  the  print  appears  dull  and  indis- 
tinct, and  the  finer  details  illegible,  or  even  invisible,  the 
surfaces  are  imperfect  and  faulty,  for  the  rays  proceeding  from 
the  various  points  of  the  object  are  not  refracted  to  their  cor- 
responding points  in  the  image. 

Indistinctness  may  be  caused  by  spherical  aberration. 

To  test  this,  cover  the  object-glass  with  a  ring  of  black 
paper,  reducing  the  aperture  to  one-half;  again  focus  small 
print  to  distinct  vision;  remove  the  ring  of  black  paper  and 
cover  the  center  of  the  object-glass  (previously  left  open),  then 
mark  how  much  the  object-glass  has  to  be  moved  in  or  out  for 
distinct  vision.  If  the  spherical  aberration  has  been  reduced 
to  a  minimum,  very  little,  if  any,  slide  motion  is  necessary  to 
obtain  a  distinct  view  under  both  tests.  The  amount  of  move- 
ment, however,  constitutes  a  measure  for  the  spherical  aberra- 
tion of  the  object-glass. 

Another  test,  but  not  as  good  as  the  one  just  mentioned,  is 
to  focus  an  object  to  distinct  vision;  then  slide  the  object-glass 
in  or  out,  observing  at  the  same  time  the  quantity  of  motion 


THE    A.    LIETZ    COMPANY,  73 

necessary  to  render  the  object  indistinct.  If  the  spherical  ab- 
erration is  completely  corrected,  the  object  should,  theoretically, 
be  rendered  indistinct  by  the  slightest  motion  of  the  lens;  but, 
practically,  this  is  not  the  case,  as  the  eye  will  accommodate  itself 
in  a  measure  to  the  difference  of  divergence  of  the  rays,  caused 
by  the  motion,  in  or  out,  of  the  object-glass,  in  the  same  manner 
as  it  will  accommodate  itself  to  near  and  distinct  objects  when 
viewing  without  the  aid  of  lenses.  So,  if  the  image  formed  by  a 
perfect  object-glass  is  viewed  by  another  perfect  lens  of  long 
focal  length,  say  six  inches,  the  object-glass  might  be  moved  in 
or  out  one-fourth  of  an  inch  from  the  point  of  distinct  vision, 
and  the  object  will  still  appear  comparatively  clear,  as  the  one- 
fourth-inch  motion,  with  an  eye-lens  of  such  long  focal  length, 
cannot  cause  enough  difference  in  the  divergence  of  the  rays  to 
prevent  the  accommodation  of  most  eyes  to  it.  The  shorter  the 
focal  length  of  the  eye-lens,  the  more  rapid  will  be  the  change 
of  divergence  or  convergence  of  the  rays  with  a  certain  amount 
of  motion;  therefore,  the  second  test  is  only  applicable  with 
eye-pieces  of  very  high  power,  which,  at  the  slightest  motion 
in  or  out,  will  cause  a  sufficient  amount  of  divergence  of  the 
rays  to  prevent  the  accommodation  of  the  eye  to  the  change. 

To  test  the  chromatic  aberration,  either  a  celestial  body  or 
a  white  disc  should  be  selected  for  an  object. 

Focus  the  object  to  distinct  vision,  thereupon  move  the 
object-glass  slowly  in  and  out  alternately.  If,  in  the  first 
instance,  a  light  yellow  ring  is  seen  at  the  edge  of  the  object, 
and  in  the  second  one  a  ring  of  purple  light,  the  object-glass 
may  be  considered  perfect,  as  it  proves  that  the  most  intense 
colors  of  the  prismatic  spectrum  (orange  and  blue)  are  corrected. 

To  test  the  flatness  of  field,  take  a  square,  flat  object,  the 
sides  of  which  are  about  four  inches  long  and  perfectly  straight 
—  the  best  object  is  a  heavily-lined  square,  drawn  on  white 
paper  with  india  ink.  Sight  this  object  from  such  a  distance 
that  it  will  nearly  fill  the  field  of  view  of  the  telescope,  and  see 
if  it  still  appears  flat  and  its  sides  perfectly  straight;  if  so,  the 
telescope  is  a  good  one.  If,  on  the  contrary,  the  object  appears 
distorted,  i.  e.,  if  the  sides,  instead  of  being  straight,  form 
curves  and  the  surfaces  appear  concave,  instead  of  flat,  the  tel- 


74  MODERN    SURVEYING    INSTRUMENTS, 

escope  is  not  good,  for  it  shows  that  the  proportions  of  foci, 
aperture  and  distances  between  the  different  lenses  are  not  ac- 
cording to  the  laws  of  optics;  owing,  generally,  to  the  attempt 
to  force  the  magnifying  power  beyond  its  limits. 

As  all  the  refractions  of  light  in  the  telescope  are  caused  by 
flat  and  spherical  surfaces,  it  is  evident  that  the  edge  of  a  round 
flat  object,  when  used  for  the  above  test,  cannot  be  distorted, 
but  that  the  surface  only  will  appear  concave  to  a  keen  observ- 
ing eye.  A  telescope  which  distorts  the  image  to  a  perceptible 
degree,  will  not,  however,  cause  any  errors  in  common  use,  if 
only  one  point  in  the  lens  is  taken  in  all  observations,  but  it  is 
decidedly  objectionable  in  stadia  measurements,  where  two 
points  in  the  field  of  view  are  used  at  the  same  time. 

To  Find  the  Magnifying  Power  of  a  Telescope. 

A  practical  method  for  finding  the  magnifying  power, 
available  to  anyone,  which  does  not  require  any  apparatus, 
taking  up  only  a  few  moments  time,  is  the  following: 

Set  up  the  instrument,  and  about  twenty  or  thirty  feet 
therefrom  hold  up  a  graduated  rod.  Observe  the  rod  \vith  one 
eye  by  direct  vision,  and  with  the  other  through  the  telescope. 
Assume  a  certain  space  on  the  rod,  say  the  height  of  a  numeral, 
or  two  sharply-drawn  lines,  and  count  the  number  of  divisions 
on  the  rod  in  that  space;  then  observe  the  number  of  divisions 
that  are  seen  by  the  naked  eye  in  the  same  space  enlarged. 
The  ratio  between  the  two  is  the  power  sought.  It  is  the  read- 
ing of  a  magnified  space  of  known  length  on  the  graduated  face 
of  the  rod.  With  a  little  practice  both  eyes  will  be  able  to  dis- 
tinguish the  rod  divisions  at  the  same  time.  If  what  is  known 
to  be  0.1  of  a  foot,  is  enlarged  by  viewing  it  through  a  telescope 
so  as  to  cover  the  space  of  2.4  feet  as  seen  by  the  unaided  eye, 
the  magnifying  power  is  24  for  the  distance  in  focus.  The 
real  power  is  somewhat  less,  for  as  the  tube  of  the  telescope  is 
drawn  out  for  near  objects,  the  power  necessarily  increases. 
The  magnifying  power  obtained  by  this  method  holds  good  for 
the  distance  that  the  rod  can  be  read  by  the  unaided  eye,  and 
it  is  always  somewhat  greater  than  the  actual  power. 

It  is  well  for  the  engineer  to  make  a  test  of  the  power  of  a 


THE    A.     LIETZ    COMPANY.  75 

telescope  himself,  for  it  is  to  the  interest  of  the  maker  to  rate 
this  higher  than  it  really  is,  for  very  obvious  reasons.  This 
method  suggests  itself  as  perfectly  practicable,  and  is  readily 
tried  at  the  time  of  purchase. 

For  a  very 'accurate  determination  of  the  magnifying  power, 
it  is  necessary  to  ascertain  the  focal  length  of  the  objective  and 
that  of  the  eye-piece,  in  order  to  compare  them  and  to  find  their 
proportion.  While  the  former  is  easily  obtained  by  a  direct 
measurement  from  the  objective  lens  to  the  cross-hairs,  the  lat- 
ter, usually  containing  an  entire  system  of  lenses,  presents 
numerous  difficulties.  For  this  purpose  we  possess  an  apparatus, 
which  was  especially  designed  and  built  for  us  by  a  prominent 
optician  in  Germany,  and  which  is  so  perfectly  adjusted  to  do 
its  work,  that  we  think  it  of  interest  to  explain  it  in  a  general 
way. 

Referring  to  the  accompanying  illustration: 

Upon  an  iron  base  F  stands  the  pillar  E,  carrying  the 
cross  bar  D,  upon  which  three  standards  are  mounted.  At 
one  end  of  the  bar  the  microscope  A  is  held  by  a  fixed  stand. 
Its  tube  is  adjustable  to  focus  by  the  screw  a.  At  the  other  end 
is  the  collimator  B,  which  slides  upon  the  bar  and  is  held  by 
the  screw  d.  Between  the  two  is  the  holder  for  the  eye-piece  C 
under  consideration.  The  pillar  slides  upon  the  bar,  and  is 
clamped  by  the  screw  c.  The  screw  b  raises  or  lowers  the  small 
platform  on  which  the  eye-piece  rests.  The  whole  is  recognized 
fully  in  the  drawing. 

To  determine  the  focal  length  of  any  lens  or  combination, 
the  eye-piece,  etc.,  is  placed  on  the  platform  as  shown,  the  col- 
limator being  turned  with  its  small  opening  e  towards  the  light. 
(It  may  be  used  in  the  daytime,  or  by  lamp-light  at  night.) 
The  whole  is  properly  adjusted  by  sliding  the  collimator  and 
the  platform  on  the  bar  as  required.  The  eye-piece,  which 
has  been  carefully  aligned  between  collimator  and  microscope, 
is  then  viewed  by  the  latter,  which  is  focused  by  the  screw  a, 
until  t.he  collimator  opening  e  is  clearly  and  distinctly  visible  as 
a  round  disc  of  light  with  a  sharply-defined  outline.  In  the 
field  .of  the  microscope  a  small  graduated  scale  is  seen,  and  by 
this  scale  the  diameter  of  the  light  disc  may  be  measured,  by 


I 


f 


MODERN    SURVEYING    INSTRUMENTS,  77 

simply  counting  the  number  of  lines  that  it  covers.  These 
give  the  focal  length  of  the  eye-piece  directly  in  millimeters, 
and  that  with  absolute  accuracy. 

Dividing  the  focal  length  of  the  objective  (when  the  tele- 
scope is  focused  to  mean  distance)  in  millimeters,  by  the  value 
just  obtained,  gives  the  magnifying  power  of  the  telescope  under 
consideration. 

This  apparatus  measures  focal  lengths  up  to  8  centimeters 
(3£  inches).  It  is  applicable  to  simple  lenses,  as  well  as  to  any 
combination  of  them.  Even  concave  lenses  may  be  determined 
by  it,  but  in  that  case  the  image  lies  behind  the  lens,  and  the 
device  will  measure  until  the  lens  touches  the  microscope,  and 
no  further. 

This  is  the  only  apparatus  of  the  kind  ANYWHERE,  as  it 
was  especially  designed  for  us,  and  built  for  the  exclusive  use  of 
the  Company. 

If  any  of  our  customers  want  the  focal  length  of  an  eye- 
piece determined,  we  shall  cheerfully  do  so,  without  charge, 
upon  receipt  of  it,  which  should  be  sent  carefully  packed  by 
express. 

Adjustments  of  the  Plane  Table  Alidade. 

Without  going  again  into  all  the  details  of  instrumental 
adjustments,  it  behooves  us  to  enumerate  the  points  required  of 
this  instrument  when  in  proper  condition.  These  are: 

1st — That  the  fiducial  edge  of  the  rule  be  absolutely  straight; 

2d  — That  all  parallax  be  destroyed,  by  placing  the  cross- 
hairs in  proper  focus; 

3d  — That  the  line  of  collimation  move  in  a  vertical  plane; 

4th — That  this  plane  be  normal  to  the  plane  of  the  ruler; 

5th — That  the  same  plane  also  intersect  the  fiducial  edge 
of  the  ruler,  or  at  least  be  parallel  thereto; 

6th — That  during  parallelism  of  the  optical  axis  and  the 
fiducial  edge,  the  zeros  of  the  vertical  arc  and  its  vernier  cor- 
respond. 

This  instrument  is  used  in  the  topographical  departments 
of  the  U.  S.  Coast  and  Geodetic  Survey,  and  the  U.  S.  Geological 


78  THE    A.    LIETZ    COMPANY. 

Survey,  and  is  exclusively  applied  in  mapping  the  topograph- 
ical features  of  the  country  in  Europe,  usually  by  officers  of  the 
army,  who  control  these  surveys,  after  the  triangulation  points 
have  been  established. 

This  method  of  surveying  has  been  constantly  improved 
in  practice,  particularly  by  the  experts  of  the  Geological  Survey, 
and  it  may  be  safely  said  that,  with  the  required  accuracy, 
nothing  surpasses  it  for  small-scaled  work  in  speed  and  applica- 
tion. All  the  bulky  parts  of  the  table  have  been  reduced  to  a 
minimum,  so  that  it  may  be  handled  with  comparative  ease  in 
the  roughest  mountain  country. 

We  refer  our  readers  to  appendix  No.  22  of  the  Coast  Survey 
Report  of  1865,  which  may  be  had  separately  in  bound  book 
form,  called  The  Plane-Table  and  its  Uses,  as  an  excellent  theo- 
retical and  practical  treatise  of  this  interesting  subject. 


III. 


PROFESSIONAL  PAPERS 


PUBLISHED     BY 


THE  A.  LIETZ  COMPANY, 


SAN    FRANCISCO. 

189  6 


NO.    1. 


A  SHORT  AND  PRACTICAL  TREATISE 
T  A.  ID  I  A 


T  JLB  J^KS 
For  the  Determination  of  Horizontal  Distance  and  Elevation. 


WRITTEN  FOR  THIS  MANUAL  BY 
OTTO  VON  GELDERN. 


The  value  of  this  method  of  obtaining  distances  is  now  so  generally  appreciated, 
that  every  engineer  will  use  it  in  his  work,  wherever  the  accuracy  obtainable  is  suf- 
ficient for  his  purpose.  While  it  cannot  replace  the  usual  means  of  precise  linear 
measurements  employed  in  cadastral  surveys,  it  offers  many  other  advantages  that 
cannot  be  too  highly  estimated.  Under  difficult  topographical  conditions  the  results, 
if  carefully  obtained,  may  be  even  better  than  those  of  the  ordinary  chain.  At  all 
events,  the  rapidity  with  which  distances  may  be  measured  at  all  times,  and  its 
adaptability  to  inaccessible  places,  have  given  it  that  prominence  in  topographical 
work  which  it  justly  deserves. 

To  make  quick  and  reliable  observations  of  this  character,  the  instrument  used 
should  be  a  good  one,  and  its  telescope,  above  everything  else,  must  possess  power, 
definition  and  light  in  a  high  degree,  in  order  to  enable  the  observer  to  read  the  so- 
called  telemeter  rod  with  precision  on  long  sights. 

The  Principle  of  the  Stadia  Method. 

The  fundamental  basis  underlying  this  method  of  measuring  is  well  known,  and 
is  simply  the  geometrical  proposition  that  parallel  lines  subtending  the  same  angle 
from  a  given  point,  are  proportional  in  length  to  their  distances  from  that  point. 
This  explains  generally  the  applied  principle  governing  the  stadia;  all  the  modifica- 
tions of  it  are  due  to  the  structure  of  the  instrument  used,  and  to  certain  optical 
and  geometrical  principles  that  involve  corrections  to  be  introduced  under  certain 
conditions  of  sight. 

By  placing  two  additional  horizontal  threads  in  the  telescope,  at  equal  distances 
from  the  middle  hair,  we  obtain  a  gauge  that  may  be  applied  to  a  graduated  rod, 
the  intercepted  space  upon  the  rod  increasing,  as  the  distance  between  it  and  the 
telescope  increases.  If  the  graduation  to  some  adopted  unit  of  measure  be  so 
marked,  that  it  may  be  read  clearly  and  distinctly  without  error  on  longer  distances, 
it  is  evident  that  a  mere  inspection  of  the  rod  by  means  of  the  telescope,  will  be 
sufficient  to  indicate  its  distance  from  the  instrument. 

The  threads  may  be  inserted  at  random,  and  the  rod  marked  to  correspond  to 
known  distances;  or  they  may  be  placed  so  as  to  intercept  one  unit  of  measure  on 
the  rod  to  a  given  number  of  units  in  distance.  The  latter  is  that  generally  em- 
ployed, and  the  usual  ratio  is  1  in  100. 


THE    A.    LIETZ    COMPANY. 


81 


When  the  distance  measured  between  two  points  is  at  an  angle  with  the  horizon, 
it  becomes  possible  to  determine  the  co-ordinates  of  horizontal  distance  and  differ- 
ence in  elevation  of  the  triangle,  provided  the  angle  of  the  slope  is  known.  This 
may  be  read  on  the  vertical  arc  of  the  instrument.  If,  in  such  cases,  the  telemeter 
rod  be  held  at  right-angles  to  the  line  of  sight,  the  horizontal  distance  will  equal 
the  cosine  of  the  observed  vertical  angle,  multiplied  by  the  distance  indicated  by 
the  rod.  This  must  be  corrected  by  certain  small  values,  to  which  reference  will  be 
made  further  on.  And  similarly  does  the  sine  of  the  angle  indicate  the  difference 
in  eievatioii. 

The  usual  custom  here  is  to  hold  the  rod  vertical  under  all  conditions,  which  is 
more  readily  accomplished,  and,  in  certain  localities,  perhaps  the  only  possible  way 
of  holding  it. 

Optical  Features  and  the  Constants  c  and  k. 

Certain  optical  principles  do  not  admit  of  a  stadia  measurement  from  the  point 
occupied  by  the  center  of  the  instrument,  but  from  a  point  outside  of  the  objective 
lens,  equal  in  distance  to  its  focal  length.  This  gives  rise  to  a  certain  value  by 
which  the  stadia  distance  must  be  increased,  and  which  may  be  practically  a  constant 
for  any  length.  It  may  be  determined  with  sufficient  accuracy  by  adding  two  meas- 
urements, taken  with  an  ordinary  scale  or  tape,  from  the  object  glass  of  the  tele- 
scope, when  the  latter  is  focused  to  a  distant  object:  one  to  the  capstan-headed 
screws,  holding  the  diaphragm  with  the  cross-hairs,  and  the  other  to  the  center  of 
the  axis.  The  sum  of  these  two  (f-\-  h,  figure  1)  is  the  constant  c,  which  must  be 
added  to  every  horizontal  distance,  irrespective  whether  long  or  short. 


In  figure  1,  let  a  =any  rod  reading,  K  =  a  constant  expressed  by  the  relation 
of  the  distance  between  the  stadia  threads  and  the  focal  distance  of  the  object  glass, 
then  K  a  =  d  —  distance  from  the  focal  point  to  the  rod,  for 

8     :    /     :  :     a     :     d  ,     or 


(1) 


wherein     _Z_     represents  the  constant  K. 


It  must  be  mentioned,  however,  that  this  is  not  strictly  correct,  because  the 
focus  is  changed  with  the  distance  of  the  object,  and  the  value  f  therefore  variable. 
Nevertheless,  the  results,  unless  obtained  on  very  short  ranges,  are  as  close  as  re- 
quired for  the  purpose  of  the  stadia,  by  assuming  •?  as  a  constant  of  any  value 

s 

that  we  may  choose  to  assign  it  when   we  place  the  hairs,  the  ratio  1  :  100  being 
usually  adopted. 

To  express  the  distance  D  of  the  rod  from  the  point  occupied  by  the  instru- 
ment, on  a  level  surface,  we  have,  therefore, 

(2)  D    =   K  a   +   c   , 


82  MODERN  SURVEYING  INSTRUMENTS, 

remembering  c  as  the  constant  expressing  the  distance  from  the  center  of  the  in- 
strument to  the  outer  focus  of  the  objective,  which  must  be  added  in  every  case. 

If  K,  as  customary,  equal  100  and  c  =  1.15'  (as  in  the  ordinary  large  transit), 
then  D  =  100  a  -f-  1.15',  so  that  the  following  rod  readings  would  correspond  to  the 
distances  as  shown: 

1        foot  =  100 ft-  +  1.15  ft-  ==  101.15  feet. 

1.69  feet  =   169ft-  +   l.lf>ft-  =  170.15     " 

2.33    "     =  233 ft-  +  1.15ft-  s=  234.15     " 

1     meter^    100"'-+  1.15ft    =  100.35  meters, 
and  so  on. 

Reduction  of  Elevated  or  Depressed  Sights. 

If,  now,  the  observation  be  made  on  a  slope  with  rod  held  vertically,  the  angle  of 
elevation  or  depression  may  be  expressed  by  n,  and  the  angle  intercepted  between 
the  stadia  hairs  by  2  m. 

Any  rod  reading  a  may  then  be  reduced  to  the  reading  aL,  or  normal  rod  read- 
ing, by  the  following  formula,  which  is  obtained  from  the  elements  given  in  the 
diagram,  figure  2: 

a 


cos  n  -}-  £  sin  n  [  tan  (n  -\-  m)  -f-  tan  (n  —  m)  ] 
Now,  since  the  angle  m   in  an  instrument  rated    1  :  100  only   amounts  to    17 
minutes,  it  is  evident  that  the  expression 

£  sin  n  [  tan-  (n  -\-  m)  -\-  tan  (n  —  m)  \ 

is  almost  the  same  as  sin  n  tan  n,  the  difference  being  so  small  that  it  will  not  be 
noticeable  at  all  in  any  of  the  stadia  requirements,  and  writing  sin  n  tan  n  in  terms 

of  the  cosine,  we  have !          ' —  ,   and  substituting  in  formula  (3),  it  will  reduce 

cos  n 
to  the  simple  expression 

(4)  al  =  a  cos  n. 

This,  then,  is  the  normal  rod  reading,  which,  by  applying  the  constant  A',  gives 
the  distance  K  a  cos  n  ,  representing  the  hypothenuse  A  of  a  right-angled  triangle, 
of  which  the  horizontal  distance  d  and  the  difference  in  elevation  e  are  the  co-ordi- 
iiates.  Their  values  in  turn  are  proportional  to  the  cosine  and  sine  of  the  angle  n, 
so  that  the  distance 

(5)  d  =  K  a    cos  2  n    , 

and  the   elevation      e  =  K  a    cos  n    sin  n    ,     which  is 

(6)  e  =  Ka    i    sin.    2  n  . 

(It  is  understood,  in  the  case  of  the  difference  in  elevation  between  the  two 
points  (e.),  that  the  middle  hair  touches  the  rod  at  a  mark  corresponding  to  the 
height  of  the  instrument,  as  shown  in  figure  2.) 

Introducing,  now,  our  constant  c  ,  which  causes  corrections  also  dependent 
upon  the  angle  n ,  we  must  add  to  the  horizontal  distance  d  the  value  c  cos  n  ;  and 
to  the  elevation  e  the  value  c  sin  n  ,  so  that  the  corrected  horizontal  distance  i.3 

(7)  D  =  c  cos  n  -f-  K  a  cos  2  n     ,     and  the  corrected  elevation 

(8)  E  =  c  sin  n  -\-  K  a  J  sin  2  n  ; 
or,  if  the  constant  K  =   100  , 

and   the  constant    c   =       1.15  , 

then  D  =       1.15  cos  n  +   100  a  cos  2  n  , 
and     E  ±=         1.15  sin  n  -j-   100«  *  sin  2w  . 


> 


84  THE    A.     LIETZ    COMPANY. 

If,  for  example,  the  rod  reading  a  be  2.22  feet,  and  the  vertical  angle  n  ~  20°, 
then 

D  —  (1.15  X  cos  20°  =  1.08)  -f-    (  222  X  cos2  20°  ==  196.03)  =  197.11  ft. 


E  =  (1.15  X   sin  20°  =  0.40)  +       222   X         __    =   71.35  71.75  ft. 

The  second  member  of  the  equation  is  the  important  one,  and  that  which  char- 
acterizes the  formula,  the  first  being  small  and  a  constant  for  the  same  angle,  inde- 
pendent of  the  distance.  But  as  it  cannot  well  be  neglected  altogether,  it  is 
customary  —  since  it  is  not  readily  incorporated  in  tabular  values  —  to  supplement 
a  table  that  shall  furnish  the  values  of  d  and  e  for  different  angles  of  inclination, 
by  the  terms  c  cos  n  and  c  sin  n  in  a  special  place,  usually  at  the  bottom,  where 
they  may  be  readily  found  and  applied.  They  vary  so  little  from  degree  to  degree 
that  for  the  ordinary  stadia  measurements  they  may  be  entirely  neglected. 

The  annexed  tables  were  calculated  by  the  formula 

d  =  K  a  cos  2  n 
c  =  K  a  \  sin  2  n  , 

and  so  arranged  as  to  give  the  distance  d  and  the  elevation  e  for  every  2  minutes  of 
arc  for  a  value  of  K  a  =  100,  the  rod  held  vertically.  They  admit  of  a  simple  appli- 
cation. 

By  what  has  preceded,  let  it  be  required  to  find  the  horizontal  distance  and  the 
difference  in  elevation,  when  the  rod  indicated  285  feet  and  the  vertical  arc  10°  12'. 
Look  for  the  column  headed  10°;  run  down  this  column  with  your  finger  to  the 
figure  on  the  same  line  with  number  12  in  the  left-hand  or  minute  column,  where, 
for  100  feet,  d  is  found  as  96.86,  and  e  17.43.  Multiply  both  of  these  by  2.85.  This 
reduces  the  distance  285  feet  to  d  =  276.05',  and  e  =  49.67'.  At  the  bottom  of  the 
page  will  be  found  values  of  the  corrections  due  to  c  for  different  focal  lengths. 
Three  values  obtain:  1.90  (the  large  Y-  level),  1.15  (the  large  transit),  and  0.75  (the 
small  transit).  If  a  large  transit  has  been  used  we  look  for  the  corrections  corre- 
sponding to  c  =1.15,  and  in  the  case  before  us  we  would  obtain  1.13  and  0.21. 
These  are  added  to  the  values  already  obtained,  and  we  have: 

corrected  horizontal  distance  D  =  277.18  feet, 
and  corrected  difference  in  level  E  =    49.88  feet. 

The  Stadia  Board  or  Telemeter  Rod. 

For  stadia  work  an  ordinary  leveling  rod  may  be  used,  and,  with  the  aid  of  a 
pocket  level  (a  so-called  rod  level  with  a  circular  bubble,  that  maj'  be  fitted  and  held 
to  the  edge  of  the  rod),  its  vertical  position  may  be  assured.  By  employing  two 
targets  and  reading  them  with  care,  the  results  will  be  as  precise  as  the  telescopic 
power  admits.  It  is  usual,  however,  in  order  to  save  time,  to  prepare  a  self-reading 
rod,  so  marked  that  it  shall  facilitate  rapid  observation  and  reduce  all  chances  of 
error  from  a  wrong  reading.  Many  patterns  are  employed  by  a  combination  of  geo- 
metrical figures  and  by  different  colors  (red,  black,  white),  that  are  intended  to 
indicate  at  a  glance  the  space  between  the  upper  and  lower  hair  in  terms  of  the  rod 
measure.  These  patterns  are  either  painted  directly  on  a  board  from  10  to  12  feet 
long,  that  may  be  folded  for  convenience  in  transportation  by  a  hinge  in  the  middle, 
or  on  stiff  canvas,  in  which  case  it  may  be  rolled  up  for  carrying  in  the  pocket,  and 
tacked  to  a  suitable  board  whenever  required.  These  so-called  flexible  stadia  boards 
answer  very  well,  but  the  former  are  to  be  preferred  in  accuiate  work,  as  they  can- 
not be  materially  distorted  by  conditions  of  weather. 


MODERN    SURVEYING    INSTRUMENTS,  gg 

In  case  the  stadia  hairs  were  set  arbitrarily,  it  becomes  a  simple  matter  to  ascer- 
tain the  constant  K.  A  distance  of  eight  hundred  feet  or  more  is  laid  off  on  a  level 
surface  with  a  steel  chain,  and  marked  at  each  hundred  feet.  The  instrument  is 
placed  the  distance  of  its  constant  c  away  from  one  of  the  end  points,  and  readings 
are  taken  on  a  leveling  rod  at  every  hundred-foot  mark.  From  these  the  ratio  between 
distance  and  rod  reading  is  readily  determined . 

Or,  a  stadia  board  may  be  so  divided  that  a  unit  of  its  measure  shall  agree  with 
a  hundred-foot  space.  If  a  blank  board  be  held  at  every  hundred-foot  mark  on  the 
ground,  we  may  draw  upon  it  the  intersection  of  the  upper  and  lower  hair  for  each 
station.  If  the  rod  units  so  obtained  vary  slightly  from  each  other,  the  mean  of 
them  may  be  adopted  without  appreciable  error,  which  is  subsequently  divided  into 
smaller  spaces,  to  read  as  close  as  desirable.  In  this  wise  we  obtain  a  rod  corre- 
sponding with  the  instrument  of  which  it  then  becomes  a  part. 

Some  instruments  possess  adjustable  stadia  wires.  In  that  event  the  hairs  may 
be  set  to  suit  the  rod. 

In  all  these  cases  it  is  evident  that  the  constant  c  must  be  previously  determined 
and  properly  applied. 

General  Remarks. 

In  making  a  stadia  observation,  after  having  set  up  and  adjusted  the  transit  over 
a  point,  direct  the  telescope  to  the  rod  and  clamp  the  instrument  in  position.  Move 
the  telescope  in  a  vertical  plane,  until  the  middle  hair  of  the  three  intersects  a  line 
on  the  rod  as  high  above  the  ground  as  the  telescope  axis  is  over  the  point  occupied, 
and  read  the  space  intercepted  between  the  upper  and  lower  hair.  An  even  foot- 
mark, or  unit-mark,  can  always  be  found,  upon  which  either  the  upper  or  lower 
hair  may  be  placed,  that  will  satisfy  the  conditions  nearly  under  which  a  should  be 
taken,  and  from  it  the  rod  may  be  read  quickly  up  or  down.  To  obtain  the  vertical 
angle,  the  telescope  should  then  be  moved  either  up  or  down  with  its  tangent 
screw,  to  the  exact  intersection  on  the  rod  corresponding  to  the  height  of  the  in- 
strument—  which  is  4.5'  ordinarily  — and  the  vertical  arc  read. 

There  are  occasions  when  the  middle  hair  cannot  be  placed  on  the  rod  as  ex- 
plained —  in  the  woods,  for  instance,  when  parts  of  the  rod  may  be  covered  by 
leaves  —  and  in  that  event  we  may  read  it  wherever  its  exposed  space  permits,  and 
make  the  necessary  corrections  afterwards.  It  is  one  of  the  particular  advantages 
of  the  stadia  that  it  may  be  used  under  very  unfavorable  conditions  of  the  field,  in 
forests,  swamps,  along  declivities,  etc.,  and  yet  obtain  very  reliable  results.  As 
long  as  the  rodman  is  able  to  get  to  a  place  and  to  hold  up  his  rod,  and  the  observer 
can  see  a  clear  space  on  the  face  of  it,  the  reading  may  be  obtained  that  shall  lead 
to  the  determination  of  the  horizontal  distance  and  to  the  difference  in  elevation. 

In  cases  where  both  stadia  wires  are  not  visible  on  the  rod,  the  space  between 
the  middle  hair  and  the  visible  one  may  be  read  off  and  multiplied  by  2,  it  being 
presumed  that  the  upper  and  lower  are  equi-distant  from  the  middle  hair.  But 
where  very  large  vertical  angles  accompany  the  sight,  however,  it  is  not  well  to  rely 
absolutely  upon  the  result,  for  it  is  quite  readily  demonstrated  that  the  horizontal 
distance  will  be  either  too  large  or  too  small  by  a  quantity,  that,  in  a  rod-reading  of 
5,  doubled  to  10  feet,  for  instance,  with  a  constant  K  =  100,  an  angle  n  =  40°,  will 
come  within  about  *$%  of  the  correct  value.  With  a  vertical  angle  of  20°  under  the 
same  conditions,  the  error  in  distance  is  about  2  $.  In  the  former  case  the  correc- 
tion would  be  plus  or  minus  2.43,  and  in  the  latter  plus  or  minus  1.59  feet.  But  it 
shows  that  even  under  the  most  unfavorable  conditions  of  sight  we  are  able  to 
approach  the  true  distance  within  all  the  requirements  of  topographical  surveying. 


36  THE    A.    LIETZ    COMPANY. 

A  survey  may  be  made  with  the  stadia  altogether,  or  \t  may  be  preceded  by  a 
triangulation,  in  order  to  locate  a  number  of  fixed  points  —  the  relative  elevations 
of  which  are  established  with  a  leveling  instrument — between  which  the  topography 
is  filled  in  with  the  stadia.  The  latter  method  is  necessarily  more  trustworthy,  and 
should  always  be  adopted  where  large  areas  are  to  be  surveyed;  but  if  the  engineer 
is  pushed  for  time,  he  may  omit  the  triangulation  and  yet  obtain  very  good 
results.  In  siich  an  event  great  care  should  be  exercised  in  locating  the  turning 
points.  Occupying  point  1  and  observing  upon  point  2,  read  carefully  the  azimuth 
on  the  plate,  and  check  it  by  recording  the  bearing  of  the  needle  also.  Head  your 
distance  from  the  rod  and  record  that.  Having  placed  the  middle  horizontal  hair 
on  the  rod  as  high  above  its  foot  as  the  telescope  axis  is  over  point  1,  observe  the 
vertical  angle,  which  is  either  plus  or  minus,  and  note  it  down.  Leaving  point  1 
and  proceeding  to  point  2,  set  the  instrument  over  the  latter  and  level  up.  It  may 
be  clamped  upon  any  desired  known  azimuth,  but  the  reading  of  the  plate  should  not 
be  omitted  in  a  direction  toward  point  1.  Record  this  with  the  bearing  of  the  needle, 
•which  will  give  the  reverse  course  of  the  sight  1  to  2.  Observe  again  the  distance 
between  the  points  as  shown  by  the  rod,  and  note  it  down,  as  well  as  the  vertical 
angle  from  2  to  1,  as  explained,  which  should  give  the  same  result  as  before  with  re- 
versed sign.  These  precautions  of  observing  twice  between  turning  points  form  a 
very  valuable  check,  and  should  never  be  omitted  where  every  other  datum  is  lack- 
ing and  the  stadia  method  alone  is  relied  upon.  After  having  taken  his  back-sights, 
the  surveyor  proceeds  with  the  observation  of  all  intermediate  points  required  for 
his  topographical  details,  before  locating  point  3  for  a  fiirther  advance. 

Work  may  be  done  still  more  rapidly  by  occupying  every  other  point  only;  but 
in  that  case  the  bearings  of  the  lines  are  solely  obtained,  by  the  needle,  and  there  is 
no  check. 

By  employing  two  or  even  three  rodinen,  distributed  about  the  field  as  ad- 
vantageously as  possible,  the  engineer  is  able  to  observe  rapidly  without  loss  of 
time.  It  is  always  well  to  have  a  recorder  accompany  the  party,  whose  sole  duty  it 
becomes  to  note  down  the  observations  of  points,  and  the  description  as  to  what 
these  points  represent.  If  necessary  and  desirable,  a  small  drawing-board  may  be 
taken  into  the  field,  and,  instead  of  a  recorder,  a  plotter  may  be  employed,  who  lays 
down  the  reduced  observations  as  the  work  progresses.  This  is  considerably  slower, 
but  it  offers  the  advantage  of  a  completed  field  map  when  the  survey  is  finished. 

Instead  of  employing  the  tables  here  given,  the  reductions  may  be  quite  expedi- 
tiously  and  accurately  made  in  the  field  by  means  of  the  logarithmic  slide,  scale,  which 
the  author  employs  in  his  surveys  altogether,  a  description  of  which  is  readily 
obtained. 

With  a  little  practice  the  engineer  will  work  himself  into  the  use  of  the  stadia, 
and  become  an  expert.  Tachymetry,  as  it  is  called,  is  an  indispensable  method  of 
measuring,  and  one  that  the  surveyor  of  to-day  must  acquire. 

Considerable  might  be  said  regarding  useful  hints  and  instructions  for  the  field, 
but  we  prefer  to  let  every  engineer  find  his  own  method  in  the  practical  application, 
knowing  well  that  after  he  has  mastered  the  principle,  he  will  adopt  a  system  of 
work  best  suited  to  his  requirements. 

The  essential  requisites  for  a  successful  operation  are  a  good  clear  telescope, 
affording  a  distinct  view  of  the  rod  on  long  ranges  (the  author  prefers  the  inverting 
eye-piece,  as  one  affording  better  light  and  a  more  distinct  image,  there  being  no 
particular  advantage  in  seeing  objects  erect,  as  the  mind  soon  accustoms  itself 
readily  to  an  inverted  vision),  a  steady  instrument,  and,  for  the  method  under  dis- 
cussion, a  true  vertical  rod . 


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No.  2. 


Principle  of  the  Logarithmic  Slide  Scale 

Written  in  1885,  but  entirely  revised  for  this  Manual  in  1893. 


BY 

HUBERT  VISCHER,  C.  E. 


The  employment  of  mechanical  devices  for  performing  computations  has  at- 
tracted the  attention  of  arithmeticians  for  a  couple  of  centuries  past,  and  to  no  class 
of  persons  is  it  of  more  direct  interest  than  to  those  engaged  in  technical  callings. 
These  endeavors  have  been  pursued  upon  several  distinct  lines,  and  we  may  notice 
by  way  of  classification: 

1st.  The  endeavor  to  perform  desired  arithmetical  operations  by  devices  dis- 
tinctly mechanical  in  their  nature,  seeking  by  skilful  combination  of  mechanical 
elements  to  carry  out  the  ordinary  sequence  followed  by  the  computer  in  making 
the  calculation.  We  may  here  mention  the  celebrated  machine  of  Babbage;  and  as 
a  more  recent  illustration,  the  "Arithmometer"  of  Thomas,  an  instrument  of  only 
moderate  cost,  and  one  coming  constantly  into  greater  use. 

2d.  The  use  of  geometrical  figures  representing  the  mathematical  relations  ex- 
isting between  mutually  dependent  quantities.  This  method,  first  suggested  by  the 
development  of  the  Des  Cartian  geometry,  has,  in  very  recent  times,  been  developed 
into  a  new  science,  graphostatics — which  does  not  merely  seek  to  present  the  de- 
ductions of  analytical  reasoning  graphically,  but  starting  at  the  elements,  builds  up 
methods  of  its  own  in  which  the  arithmetical  conceptions  of  magnitudes  fall  more 
and  more  into  the  back  ground  and  are  replaced  by  operations  which  are  mechanical 
in  application,  if  not  in  their  conception. 

Besides  these  two  methods,  we  have  another,  somewhat  partaking  in  nature  of 
both,  yet  embodying  a  distinct  principle  of  its  own,  that  of  the  Logarithmic  Slide 
Scale. 

It  is  here  proposed  to  take  a  cursory  survey  of  this  field,  which  is  of  wide  ap- 
plication and  certainly  of  interest,  being  an  important  agent  for  the  saving  of  time- 
robbing  computations.  It  is  worthy  of  more  general  attention  than  it  has  received 
in  this  country;  though  in  Europe,  the  slide-rule  is  recognized  as  the  engineer's 
daily  pocket  companion. 

The  slide-rule  rests  upon  two  most  simple  principles:  first,  that  magnitudes  in 
general  may  be  represented  by  the  length  of  lines;  second,  that  these  lines,  when 
measured  off  upon  one  another  may  represent  by  the  length  of  a  resulting  line, 
either  a  summation  or  a  difference  of  the  magnitude  which  the  lines  represent.  The 


92  THE    A.     LIETZ    COMPANY. 

first  principle  is  made  use  of  in  the  logarithmic  graduation  of  the  scales;  the  second 
principle  finds  application  in  the  sliding  motion  which  we  impart  to  the  scales. 
Slide-rules  have  been  constructed  of  many  kinds  and  for  many  special  purposes, 
but  they  will  all.be  found  to  reduce  to  these  two  elementary  principles. 

The  use  of  the  logarithmic  graduation  here,  as  in  all  other  cases  where  logar- 
ithms are  employed,  is  due  to  the  desire  to  reduce  arithmetical  calculations  by  one 
step  in  the  scale  of  operations;  thus  replacing  multiplication  and  division  by  addi- 
tion and  subtraction,  and  reducing  involution  and  evolution  to  multiplication  aiid 
division. 

The  method  in  which  the  logarithmic  graduation  is  carried  out  is  explained 
ra^st  easily  by  taking  a  special  case,  and  we  refer  to  the  scale  AB  A' Bf  on  Fig.  1. 
The  length  of  this  scale,  measured  between  the  two  extreme  outer  limits,  marked  1, 
1,  is  assumed  as  a  unit  of  length;  and  what  the  absolute  length  of  this  unit  is,  is 
perfectly  immaterial.  We  may,  for  purposes  of  illustration,  assume  it  to  be  just  one 
foot  long.  As  a  preliminaiy  step,  let  us  first  imagine  this  length  divided  off  into  say 
1,000  equal  parts.  Before  proceeding  further,  however,  let  us  recall  to  mind  the  well 
known  property  of  "periodical  repetition"  peculiar  to  the  Briggs'  system,  whereby 
all  numbers  represented  by  the  same  numerals,  grouped  in  the  same  order,  are  repre- 
sented by  the  same  logarithm,  independent  of  the  characteristic  or  mantissa. 

It  is  clear  that  with  the  aid  of  a  table  of  logarithms  and  using  our  scale  of  equal 
divisions,  we  may  at  once  assign  to  any  logarithm  in  the  table  a  place  on  the  scale, 
such  that  its  distance  from  the  zero  (or  left-hand  end  of  the  scale)  may  correctly 
represent  the  value  of  the  logarithm,  plotted  in  our  unit  or  standard  of  length.  Do- 
ing this  for  all  logarithms,  commencing  at  the  number  1,  and  progressing  by  any 
suitable  interval  (say  1-100  of  unity),  let  us  mark  each  so  determined  point  by  a  cross- 
line  on  the  scale,  and  (in  order  to  preserve  it  for  future  use)  mark  opposite  the 
cross-line  the  number  corresponding  to  the  logarithm  which  the  cross-line  fixes. 

Having  done  this,  we  reach  the  right-hand  end  of  our  scale,  when  in  our  table 
ws  reach  the  number  10.  It  is  apparent  that  our  scale  represents  graphically  a  table 
of  logarithms  for  all  whole  numbers  between  1  and  10,  with  suitable  subdivisions, 
and  corresponds  in  all  particulars  to  the  printed  table  from  which  it  was  constructed. 
But  it  is  equally  clear  that  if  we  agree  to  consider  the  scale  as  representing  the  frac- 
tional part  of  the  logarithm  only,  and  without  reference  to  the  "  characteristic,"  we 
may  at  once  extend  its  range  so  as  to  embrace  the  whole  field  of  positive  numbers 
without  any  reservation.  The  "characteristic  "  of  the  logarithm,  however,  only  de- 
termines the  position  of  the  decimal  point  in  its  number.  Therefore,  this  stipula- 
tion about  dropping  the  characteristic  implies,  conversely,  that  our  scale  shall  only 
give  us  the  numerals  which  express  a  mimber,  without  reference  to  a  decimal  point; 
so  that,  if  we  read  2,  3,  5  on  the  scale,  we  may  read  this  as  235,  or  as  235  with  any 
number  of  zeros  affixed  or  prefixed  to  it;  as  0.00235  or  as  2350,  for  example.  In 
slide-rule  calculations  there  must  always  be  some  foreign  means  employed  for  cor- 
rectly assigning  the  position  of  the  decimal  point,  a  matter  which  will  be  referred  to 
again  later  on. 

It  is  now  practically  shown  what  constitutes  the  construction  of  the  logarithmic 
scale — only  one,  however,  of  an  infinite  variety  of  possible  logarithmic  scales.  Any 
series  or  group  of  numbers  may  be  made  the  basis  of  a  similar  scale.  Thus,  by  means 
of  their  logarithms,  we  may  construct  logarithmic  scales  for  the  natural  sines  or 
tangents  of  angles  (see  scales  E  and  F,  Fig.  2),  or  for  any  other  function  of  angles; 
or,  as  the  choice  of  the  length  of  our  unit  was  left  perfectly  open,  we  may  plot  scales 
to  any  enlarged  or  reduced  scale,  which  latter  observation  is  important,  as  it  forms 


MODERN    SURVEYING    INSTRUMENTS.  93 

the  basis  of  all  operations  embodying  involution  and  evolution  in  the  slide-scale 
calculations  (as  will  at  once  appear  clear  by  remembering  that  these  operations,  log- 
arithmically speaking,  imply  multiplication  and  division). 

Returning,  however,  to  our  constructed  scale,  Fig.  1,  let  us  conceive  it  severed 
longitudinally  along  its  central  lina  by  a  cut,  a  b,  so  as  to  fall  into  two  identical 
scales,  A  A'  and  BB'.  Furthermore,  let  us  regard  these  scales  as  free  to  slide  later- 
ally to  the  right  or  the  left,  along  their  common  line  of  contact,  a  b.  With  this  mo- 
tion we  at  once  obtain  the  means  of  performing  any  desired  multiplication  or  division 
This  is  clear,  if  we  consider  that  the  divisions  upon  our  scale  are  magnitudes  logar- 
ithmically plotted,  and  that,  therefore,  an  addition  or  subtraction,  as  far  as  these 
are  concerned,  executes  a  multiplication  or  division  as  regards  their  numbers  (which 
are,  by-the-by,  the  only  records  on  the  scale).  With  this  capacity  of  motion,  we 
have  attained  the  simplest  form  of  the  slide-rule.  A  single  setting  of  the  slide  per- 
forms a  multiplication  or  division;  if  desired,  a  combination  of  both,  i.  e.,  a  propor- 
tion; and  in  many  cases  not  simply  for  a  single  set  of  numbers,  but  for  a  whole 
series  of  sets  of  numbers  at  one  and  the  same  operation.  The  details  of  manipula- 
tion are  not  entered  into  here,  having  only  the  principles  of  the  slide-rule  in  view. 
If  desired,  these  can  all  be  found  described  at  length  in  the  printed  directions  fur- 
nished with  the  scales.  Be  it  remarked,  however,  that  although  the  whole  operation 
has  been  essentially  a  logarithmic  one,  we  lose  sight  entirely  of  logarithms  having 
been  used  at  all.  This  is  always  the  case  in  operations  with  the  slide-rule.  In  fact, 
the  peculiar  merits  of  the  slide-rule  can  hardly  be  better  expressed  than  by  pointing 
out  this  unconscious  gaining  of  all  the  advantages  of  using  logarithms,  while  saved 
the  labor  of  taking  them  from  tables.  While  the  whole  conception  of  the  slide-rule 
is  logarithmic  in  its  nature,  save  as  a  means  of  understanding  its  construction  and 
in  studying  out  particular  modes  of  application  to  meet  special  cases,  this  is  lost 
sight  of  entirely  in  its  use. 

The  slide-rule,  as  constructed  by  the  firm  of  Dennert  &  Pape  (in  Altona,  Ger- 
many), is  shown  in  figures  1  and  2;  the  latter  being  an  isometrical  view  of  the  scale 
in  order  to  better  show  its  working  parts.  These  are  as  follows:  A  thin  slab  of  box- 
wood, called  the  "slide,  "upon  the  edges  of  which  two  scales,  B  and  C  are  engraved. 
The  slide  being  fitted  with  tongue-and-grooved  edges  at  its  sides,  is  free  to  move  be- 
tween two  other  boxwood  surfaces  also  bearing  scales,  A  and  D.  The  latter  are 
parts  of  the  same  piece  of  wood,  being  connected  with  each  other  underneath  the 
slide,  and  both  of  these  (together  with  the  connecting  boxwood  member)  form  the 
"rule,'1  into  which  the  slide  is  recessed  laterally  while  left  perfect  freedom  of  motion 
lengthwise,  in  both  directions.  Scales  A  and  B,  as  has  been  shown,  are  exact  dupli- 
cates of  one  another,  as  are  also  scales  C  and  D,  thus  forming  two  pair  of  scales. 
The  latter  pair,  in  principle  of  graduation  correspond  to  the  former  pair  entirely, 
but  are  graduated  to  one-half  the  scale  (or  length  of  unit)  of  A  and  B.  This  reduc- 
tion in  scale  would  make  each  of  the  upper  scales  one-half  the  length  of  the  lower 
pair,  were  it  not  that  we  utilize  the  remaining  half  by  engraving  thereon  another 
duplicate  set  of  the  smaller  scales,  placed  alongside  of  the  former;  thus  making  the 
total  length  of  the  upper  double  pair  exactly  that  of  the  single  lower  pair.  Each  half 
of  either  "  double  scale  "  is  not  to  be  regarded  as  separate  from  its  neighbor,  but  as 
joined  to  it,  so  as  to  form  one  continuous  scale;  the  idea  being  to  allow  the  double 
scales  to  represent  all  numbers  for  an  interval  of  two  whole  powers  of  10,  while  the 
lower  scales  represent  all  numbers  for  half  that  interval;  if  the  lower  scale  embraces, 
for  instance,  the  period  from  1  to  10,  then  the  upper  similarly  represents  the  period 
from  1  to  10  on  the  first  (or  left  hand)  halves,  while  the  second  (right  hand)  halves 


94  THE    A.    LIETZ    COMPANY. 

simiTltaneously  represent  the  numbers  from  10  to  100.  The  pair  of  scales  on  the 
slide  (though  movable  as  a  pair)  stand  permanently  with  their  extreme  ends  directly 
over  and  under  one  another;  so  also  stand  permanently  fixed  opposite  one  another 
the  ends  of  scales  A  and  D. 

Now,  while  the  double  scales  C  and  D,  on  account  of  their  lateral  motion  along 
their  common  line  of  contact,  answer  the  same  purposes  exactly  that  the  lower  pair 
do  (that  is,  perform  multiplication  and  division  also),  a  little  reflection  and  study 
of  the  figure  will  show  how,  regarding  A  and  D  or  B  and  C  as  pairs,  the  following 
must  always  hold  good,  on  account  of  the  peculiarities  of  the  mode  of  graduation: 
any  number  on  the  upper  scale  stands  directly  over  its  root  on  the  corresponding 
lower  scale;  and  conversely,  any  number  on  a  lower  scale  may  be  raised  to  the  sec- 
ond power  by  taking  the  corresponding  number  exactly  above  it  in  its  companion 
scale.  Thus  a  simple  transfer  made  in  a  suitable  manner,  from  either  scale  to  the 
other,  at  right  angles  to  the  axis  of  the  rule,  effects  an  involution  or  a  radicatiou  to 
the  second  degree;  and  either  of  these  operations  may  be  combined,  at  will,  with 
multiplication  and  division,  by  a  suitable  movement  of  the  slide.  *  Involution  and 
evolution  to  higher  powers  may  also  be  executed  by  the  slide-rule,  though  we  merely 
note  the  fact  here. 

The  "  slide, "  however,  can  be  completely  run  out  of  the  rule  and  re-inserted, 
when  so  desired,  reverse  side  up.  The  reverse  side  of  the  slide  bears  two  scales,  E 
and  F,  these  being  respectively  logarithmic  scales  of  natural  sines  and  natural 
tangents.  The  reverse  side  of  the  slide  also  carries  a  third  scale,  (?,  bearing  equal 
divisions  (l-1000ths  of  the  scale  length)  and  answering  the  purpose  of  a  table  of  or- 
dinary printed  logarithms,  in  which  the  numerical  value  of  any  logarithm  may  be 
directly  read  off  the  scale. t 

With  the  slide  in  the  reversed  position,  the  slide-rule  presents  the  appearance 
shown  in  Fig.  2.  When  used  in  combination  with  each  other,  scales  A,  Z>,  E  and  F 
enable  us  to  perform  any  calculation  into  which  enter  the  trigonometrical  functions  of 
angles,  combined  in  any  way,  by  multiplication,  division,  involution  or  evolution, 
with  quantities  expressed  in  simple  numbers. 

Our  slide-rule,  now  fully  equipped,  is  an  instrument  only  a  few  inches  long,  f 
suitable  for  being  carried  in  one's  breast  pocket,  and  of  but  trifling  cost.  To  enum- 
erate its  various  uses,  it  at  once  serves  as  a  table  of  numbers  and  their  squares  and 
cubes,  their  square  and  cube  roots;  it  is  at  the  same  time  a  table  of  common  logar- 
ithms of  natural  sines,  cosines,  tangents  and  cotangents.  It  is  moreover  capable  of 
mechanically  combining  any  of  the  above  functions  in  any  desired  arithmetical 
combination,  constantly  showing  up  to  better  and  better  advantage  the  more  com- 
plex the  nature  of  the  combination  is.  It  serves  also  as  a  convenient  pocket  rule 
and  straight  edge,  for  it  is  both  of  these.  It  furthermore  contains  printed  on  its 
reverse  side  a  valuable  list  of  useful  pocket  data  of  many,  frequently  used,  practical 
co-efficients.  Yet  while  being  all  these  things  combined,  alas,  absolute  perfection  is 
unattainable!  It  must  be  admitted  it  has  its  shortcomings  also.  Owing  to  the  me- 
chanical difficulty  of  graduation,  and  the  uncertainty  of  reading  results  closer  than 
to  the  third  (at  times  the  fourth)  numeral  place,  it  remains,  notwithstanding  all  its 

*  To  accurately  effect  this  transfer,  a  small  brass  part,  called  the  "runner."  is  provided.  See  Fig.  2,  A. 
This  slides  freely  along  the"  rule  in  grooves  on  its  outer  sides,  and  carries  two  indices,  a,  a,  which  accurately 
transfer  points  from  one  scale  to  another. 

t  Scale  G  is  really  the  scale  of  imaginary  equal  divisions  first  referred  to  as  a  preliminary  step  towards  gradu- 
ating our  original  scale,  A,  A'. 

t  Generally  26  centimeters,  or  10  inches. 


MODERN    SURVEYING    INSTRUMENTS.  95 

theoretical  perfection,  practically  an  instrument. only  applicable  where  no  greater 
accuracy  than  the  third  or  fourth  figure  is  required. 

Its  use  must  always  he  a  judicious,  one.  The  banker,  computing  interest  or 
exchange  upon  extended  rows  of  figures,  will  find  the  slide-rule  falls  short  of  his  re- 
quirements. Its  accuracy  is  inadequate  in  many  calculations  of  ihe  engineer,  and 
many  have  undoubtedly  cast  the  slide-rule  scornfully  aside,  only  half  examined,  on 
account  of  the  only  approximate  accuracy  of  its  determinations.^* 

These  shortcomings  freely  admitted,  it  still  remains  an  invaluable  assistant,  and 
serves  to  good  purpose  wherever  a  limited  degree  of  accuracy  is  required — and  this, 
after  all,  holds  good  in  the  vast  majority  of  cases  in  engineering  practice.  In  con- 
struction; wherever  we  have  to  deal  with  practical  co-efficients  (generally  themselves 
but  approximations);  where,  moreover,  wide  factors  of  safety  are  generally  intro- 
duced, and  where,  after  all,  practical  considerations  usually  dictate  a  selection  of  the 
nearest  marketable  standard  size — here,  alwavs,  the  slide-rule  gives  us  results  quite 
as  reliable  as  the  most  elaborate  calculation  carried  out  to  the  fifth  or  sixth  decimal 
place  1  In  estimates  of  earthwork,  where  our  surveys  are  at  best  but  close  approxi- 
mations to  the  true  condition  of  the  ground;  for  proportionately  distributing  minor 
errors;  for  interpolating  intermediate  grades;  for  at  once  transforming  quantities 
expressed  in  one  standard  unit  to  equivalents  in  another  standard  —  for  all  these 
purposes,  on  account  of  its  great  rapidity  and  freedom  from  liability  to  "mistakes," 
the  slide-rule  cannot  be  too  highly  estimated. 

It  may  not  be  equal  to  figuring  out  traverses  to  the  one  hundredth,  or  the  one 
thousandth  parts  of  a  foot  (and  how  very  seldom  do  our  measurements  really  war- 
rant such  subsequent  super-refinements  in  calculation)  ;  yet  even  here  it  may  do 
good  service  as  a  check  against  "mistakes."  There  are  hundreds  of  cases  where  its 
use  in  the  field  may  obviate  the  many  half  hours  and  quarter  hours  consumed  — 
with  a  party  standing  idle  all  the  time — while  one  man  alone  is  busy  figuring  out 
some  field  problem  of  location.  We  have,  besides  these  cases,  another  frequently 
recurring  set;  namely,  where  the  relations  expressed  in  an  equation  are  so  complex 
as  to  make  solution  only  practical  by  continued  approximation;  or  where  we  have 
to  assume  co-efficients,  themselves  functions  of  the  element  to  be  determined;  where, 
ctssuminrj  some  probable  value  of  the  required  quantity,  we  gradually,  by  successive 
trials,  adjust  all  elements  to  conformity,  as  so  frequently  occurs  in  hydraulic  work. 
Here  we  can  always  use  the  slide-rule  advantageously  for  the  first  stages  of  the  cal- 
culation, and  when  tolerably  certain  of  being  "near  the  mark,"  we  can  then  resort 
to  ordinary  modes  of  calculation  in  the  last  and  final  stage. 

From  what  has  been  said  of  the  general  accuracy  of  the  slide-rule,  one  impor- 
tant corollary  should  be  drawn:  to  use  it  successfully,  that  is,  rapidly,  we  should 
never  waste  time  in  straining  at  the  last  hair,  either  in  setting  the  scale  or  in  reading 
a  result;  this  will  reap  no  adequate  return  for  the  extra  labor  spent. t 

One  of  the  chief  difficulties  to  beginners  in  using  the  slide-rule  lies  in  assign- 
ing to  a  result  its  correct  local  value;  that  is,  to  fix  the  position  of  the  decimal 
point.  Many  do  this  by  rule  of  thumb  entirely,  placing  the  decimal  point  by  guess- 

*  Notwithstanding  the  above  remarks,  those  who  really  make  a  study  of  it,  will  be  astonished  at  the  accuracy 
it  can  be  made  to  yield  in  the  hands  of  an  adept  The  slide-rule,  namely,  often  contains  in  itself  the  means  of 
overcoming  its  own  deficiencies.  Thus  used,  the  ordinary  limit  of  the  third  or  fourth  numeral  place  falls  away, 
and  that  of  the  sixth  or  seventh  place  appears  as  its  limit  in  its  stead.  For  instance,  any  rapidly  converging 
series  applied  to  the  rule  extends  its  range  at  once  immensely.  This  study  of  the  ultimate  possibilities  of  the 
slide-rule  and  its  special  applications  is  a  highly  interesting  one  to  any  one  with  leisure  to  devote  to  it. 

t  In  using  the  scale  this  is  essential,  as  also  that  the  slide  should  move  with  perfect  freedom,  though  not  so 
freely  as  to  slip  by  an  inadvertent  touch.  To  effect  this,  keep  the  grooves  clean,  and,  if  necessary,  lubricate  with 
a  drop  of  fine  oil. 


96  THE    A-    LIETZ    COMPANY. 

work,  whereby  mistakes  are  liable  always  to  creep  in.  The  most  satisfactory  method 
is  to  preserve  in  one's  head  the  logarithmic  characteristic  separate,  and  to  execute 
mentally  the  operation  implied  by  the  calculation,  regarded  as  a  logarithmic  prob- 
lem. The  result  of  this  simple  calculation  always  fixes  the  local  value  of  the  result 
correctly.  For  example,  say  230  is  to  be  multiplied  by  0.0003,  and  the  result  divided 
by  2.7.  Then  we  have  230  [characteristic  +  2],  0.0003  [characteristic  —  4],  2.7 
[characteristic  0];  then  _f-2  +  (—  4)  —  0  =  +  2  —  4  =  —  2.  The  slide-rule  gives 
the  figures  of  the  answer  to  four  places,  2555  (the  last  place  a  little  uncertain),  and 
from  the  foregoing  we  know  the  correct  value  of  230  -7-  2.7  X  0.0003  to  be  0.02555. 
An  additional  unit  must,  however,  always  be  added  or  subtracted  every  time  we 
have  to  resort  to  a  substitution  of  one  index  for  another  in  attaining  a  result,  or 
when  we  read  a  result  by  passing  through  an  index  (which  corresponds  entirely  to 
carrying  a  unit  or  borrowing  one  where  ordinary  logarithms  are  used).  A  little 
practice,  however,  teaches  us  how  this  is  to  be  applied.  To  illustrate:  56  X  7  —  392. 
If  not  modified,  our  rule  would  give  us  1  -f-  0  =  1,  or  39.2  as  an  answer.  To  obtain 
a  reading  at  all,  a  substitution  of  the  indices  was  required,  for  which  a  unit  must  be 
added,  when  we  have  1  -|-  0  -j-  1  =  2,  giving  the  correct  result  392.  Or,  say  we 
inquire  how  often  7  goes  into  56.  For  the  position  of  the  decimal  point,  we  would 
have  1  —  0  =  1,  or  the  answer,  80  times.  We  had,  however,  to  use  .the  right-hand 
index  to  obtain  a  reading,  where  ordinarily  the  left-hand  index  would  have  given 
us  the  answer.  This -substitution  implies  our  subtracting  an  additional  unit,  and 
we  have  1  —  0—1  —  0,  or  56  -j-  7  =  8,  the  correct  answer. 

This  calculation  is  never  too  difficult  to  be  kept  in  one's  head,  save  where  the 
operation  is  a  lengthy  one,  when  it  is  well  to  keep  the  characteristic,  as  was  done 
above  in  the  process  of  illustration,  on  a  separate  scrap  of  paper,  or  to  provide  the 
slide-rule  with  some  distinct  recording  device  for  keeping  the  characteristic.  A 
simple  device  for  this  purpose  is  that  of  Mr.  Deering,  of  the  Southern  Pacific  B.  K. 
A  small  annular  disc,  free  to  revolve  around  a  center,  upon  which  a  radial  scratch 
used  as  an  index  is  marked,  is  provided  with  several  radial  divisions  to  either  side 
of  a  central  initial  mark  or  zero.  The  disc  is  turned  a  suitable  number  of  places  to 
the  right  or  left  to  record  the  characteristic,  when  the  slide  is  set  to  the  number  and 
its  position  shifted  appropriately  at  each  stage  of  the  operation;  the  index  on  the 
fixed  center  finally  indicating  the  correct  position  of  the  decimal  point.  This  little 
device  is  mounted  on  the  runner  of  the  slide-rule,  au'd  can  be  easily  turned  with  the 
finger  while  one  manipulates  the  runner. 

We  will  now  close  our  observations  on  the  ordinary  slide-rule,  remarking  that 
figures  1  and  2  are  only  illustrative  representations  of  the  rule,  and  only  show  the 
main  subdivisions.  An  idea  of  the  fineness  of  the  graduation  actually  used  may  be 
derived  from  figures  3  and  4,  which  show  the  same  rule  with  the  runner  removed, 
reduced  to  about  four-fifths  the  usual  size. 

Besides  that  of  Denuert  and  Pape  the  slide-rule  of  Le  Noir  has  been  widely  in- 
troduced into  this  country,  which,  although  apparently  differing  but  slightly  from 
the  former,  falls  much  short  of  it  in  practical  efficiency.  The  most  essential  differ- 
ence consists  in  its  having  three  of  the  "double  scales,"  and  only  one  single  scale, 
instead  of  two  of  each  kind  —  and  there  is  no  runner.  Slight  variations  in  the 
arrangements  of  the  slide  make  great  differences  in  the  degree  of  serviceability. 

The  slide-rules  already  described  are  applicable  generally  to  all  calculations,  and 
there  is  no  calculation  which  cannot  be  executed  by  carrying  out  with  the  rule,  step 
by  step,  each  successive  intermediate  operation  necessary  to  attain  the  result.  This, 
however,  often  necessitates  several  settings  of  the  scale,  in  order  to  obtain  a  single 


MODERN    SURVEYING    INSTRUMENTS.  97 

result.  To  avoid  this  extended  manipulation,  special  slide-rules  maybe  constructed, 
capable  of  solving  almost  any  such  case  by  one  single,  or  at  least  by  a  greatly  re- 
duced number  of  settings  of  the  rule. 

Speaking  generally,  any  function  of  two  variables  combined  with  constants, 
may  be  solved  by  one  movement  of  a  specially  constructed  rule,  the  peculiarity  of 
the  special  construction  being  that  the  constants  are  embodied  in  a  suitable  manner 
with  the  variables  directly.  With  each  additional  independent  variable  above  two, 
one  more  movement  is  required,  generally  necessitating  the  introduction,  however, 
of  an  additional  scale. 

Figure  5  gives  an  illustration  of  this  kind,  showing  a  scale  very  widely  used  in 
Germany  in  topographical  work.  With  stadia  measurements  for  direct  readings  of 
a  vertical  rod,  we  have  the  formulae: 

d  i=   K  a  cos  '2  n  , 
e    =  K  a  \  sin  2  n  , 

where  n  is  the  angle  of  elevation  above  the  horizontal ;  K,  a  constant  dependent 
upon  the  construction  of  the  telescope,  and  generally  so  adjusted  as  to  be  exactly 
100;  a,  the  reading  on  the  vertical  rod  between  the  stadia  hairs;  d,  the  corrected 
distance  of  the  observed  point  from  the  instrument;  and  e,  its  elevation  above  the 
horizontal  plane  through  the  horizontal  axis  of  the  telescope. 

In  this  form  of  slide  scale,  we  have  the  slide  bearing  two  scales;  the  upper  scale 
graduated  to  J  sin  2  n,  the  lower  one  for  cos  2  n.  The  rule  carries  two  identically 
graduated  scales  of  simple  numbers  representing  the  rod  readings,  a.  Setting  the 
index  of  the  lower  scale  to  coincidence  with  the  rod  reading,  we  read  directly  on  the 
lower  scale  opposite  the  observed  angle  n,  the  corrected,  i.  e.,  horizontal  distance  d, 
also  on  the  upper  scale,  the  difference  in  elevation,  e.  < 

This  scale  is  very  serviceable,*  but  as  usually  constructed  is  too  long  to  be  con- 
venient for  anything  but  office  use.  There  is  another  scale  for  the  same  purpose, 
executed  in  metal,  fitted  for  being  used  in  the  field,  a  vernier  being  employed.  In 
this  case,  the  finer  metallic  graduation  is  relied  on  to  make  up  in  accuracy  what 
otherwise  would  be  sacrificed  by  the  reduced  length  of  the  scale. 

Another  direction  presents  itself  for  development  of  the  slide-rule  by  artificially 
extending  the  length  of  unit  (without  correspondingly  increasing  the  size  of  the  in- 
strument). In  his  catalogue  of  instruments,  Stanley  of  London,  describes  an  in- 
strument by  Professor  Fuller.  Here,  by  developing  the  scales  on  a  spiral  line 
upon  a  cylinder,  a  length  of  unit  equivalent  to  83  feet  is  attained,  of  course,  hereby 
very  materially  increasing  the  accuracy  of  the  slide-rule,  although  probably  not 
nearly  in  the  ratio  of  the  increased  length  (which  is  about  one  hundred-fold  that  of 
the  ordinary  slide-rule). 

*  This  scale  is  also  very  convenient  in  running  grade  lines,  enabling  the  transit-man  always  to  select  his  grade 
points  on  the  ground,  and  keep  track  of  his  elevations  without  the  aid  of  the  level,  and  judiciously  used  will 
often  save  much  "backing  up "  in  field  location. 


M 


M 


I  , 


No.    S. 

SOME    PRACTICAL    HINTS 

ON 

How  TO  TELL  A  GOOD  SURVEYING  INSTRUMENT 

By  A.  LIETZ,  Member  Tech    Soc 


Regarding  their  quality,  engineers'  instruments  may  be  divided  into  two  classes. 
In  the  lirst  category  we  would  place  those  which  are  disposed  of  by  their  makers 
directly  to  the  engineer  who  uses  them,  while  those  of  the  second  class  are  made 
for  the  trade,  and  sold  principally  by  dealers.  While  in  most  of  the  latter  class 
many  so-called  improvements  are  introduced  that  make  them  easily  salable,  they  do 
not  possess  the  thorough  workmanship  which  makes  up  a  first-class  article.  There 
are,  indeed,  many  improvements,  which  may  yet  be  added,  but  if  they  are  not  made 
in  a  thorough  workmanlike  manner  they  are  of  little,  if  any,  importance,  and  will 
in  no  case  make  an  instrument  of  tine  quality. 

Graduation. — In  a  transit,  the  graduation  is  the  most  important  part.  Solid 
silver  is  the  best  metal  known,  upon  which  a  perfect  graduation  can  be  made,  and 
it  is  therefore  almost  exclusively  used  by  makers.  It  has  the  advantage  of  keeping 
its  surface  better  than  the  silver  wash,  which  is  found  on  most  of  the  older  instru- 
ments. 


To  examine  the  graduation,  the  first  thing  should  be  to  see  whether  each  line 
is  perfectly  sharp  and  clearly  cut;  for  this  purpose  it  is  well  to  use  a  compound  mi- 
croscope, as  only  a  very  keen  observer  will  be  able  to  detect  unevenness  in  the  lines 
with  a  common  magnifier.  The  starting  point  of  a  line,  if  closely  examined,  will 
show  whether  a  perfectly-shaped  and  well-set  tool  was  used  in  cutting  it. 

The  line  shown  in  figure  A,  in  which  the  upper  or  pointed  end  is  the  starting 
point,  indicates  by  its  true  shape  that  it  could  only  have  been  made  with  a  perfect 
and  properly  set  tool.  It  is  a  fact  that  this  shape  is  found  in  all  graduations  of 
first-class  instruments. 

*  Reprinted  and  revised,  by  permission,  from  the  Transactions  of   the  Technical  Society  of   the  Pacific 
Coast.  Vo!   VII,  No.  5.  Decembei,  1890 


100  MODERN    SURVEYING    INSTRUMENTS. 

In  Fig.  B  the  line  has  no  taper,  but  begins  with  its  full  width.  In  such  an 
event  the  cut -was  either  made  from  the  inner  rim  of  the  circle  outward,  or,  what  is 
more  likely,  the  engraving  tool  was  set  end  for  end  and  drawn  from  the  starting 
point  backwards  toward  the  center.  In  most  cases  is  the  blunt  end  of  the  line  ex- 
plained by  the  latter  method.  Although  the  tool  used  for  such  a  purpose  may  have 
been  sharp  and  of  the  proper  form,  the  additional  pressure  required  to  draw  it  with 
its  wrong  end  foremost  vitiates  the  degree  of  accuracy  of  the  graduation,  for,  if  an 
unnecessary  force  is  applied  in  producing  a  line,  the  tool  will  not  always  follow  the 
motion  in  which  it  is  guided  by  its  drawing  mechanism. 

Figure  C  represents  a  line  made  with  an  imperfect  drawing  device  and  a  dull 
tool  not  capable  of  doing  good  work. 

It  will  be  noticed  in  figures  A,  B  and  C,  that  the  starting  point  of  the  line  shows 
the  shape  of  the  tool  with  which  it  was  made,  and  this  is,  therefore,  the  main  point 
upon  which  to  pass  judgment  on  the  value  of  a  graduation. 

After  we  have  convinced  ourselves  that  the  shape  of  the  line  is  perfect,  we  may 
feel  somewhat  assured  that  the  graduation  is  a  good  one;  but  if  the  lines  are  not 
equally  spaced,  they  are  worthless.  To  determine  this  is  the  most  difficult  as 
well  as  the  most  tedious  of  tests  to  be  made  in  the  examination  of  an  instrument 
with  graduated  circles.  The  manufacturers  have  apparatus  with  which  such  exam- 
inations can  be  made  in  a  comparatively  short  time,  and  with  a  great  degree  of 
accuracy.  No  maker  of  first-class  instruments  will  let  one  go  out  of  his  hands  be- 
fore having  convinced  himself  that  the  divisions  are  as  perfect  as  demanded  by  the 
character  of  the  article. 

The  most  accurate  graduation,  however,  is  of  no  value  without  a  well-fitting 
center.  To  prove  both,  several  methods  are  employed.  The  surest  test  is  to  clamp 
the  vernier  plate  to  any  point  of  the  circle,  then,  if  by  adding  the  reading  of  the 
two  verniers  together  —  frequently  repeating  this  manipulation  upon  different  parts 
of  the  circle  —  the  sum  will  always  be  180  degrees,  they  are  correct.  (This  refers  to 
plates  graduated  from  0  to  180  degrees,  on  both  sides  of  zero;  in  case  of  a  graduation 
to  360  degrees,  a  subtraction  is  required.) 

The  graduation  of  an  instrument  having  but  one  vernier  can  only  be  tried  with 
the  telescope,  which  is  a  rather  tedious  operation. 

It  may  also  be  remarked,  that  short  lines  on  a  graduated  circle  are  of  some  ad- 
vantage, as  the  spaces  between  them  appear  to  be  much  larger,  and  there  is  conse- 
quently less  fatigue  to  the  eye  while  reading.  It  is  another  fact  that  during  the 
process  of  graduating  the  tool  is  not  required  to  do  as  much  work,  and  is  therefore 
apt  to  keep  its  fine  edges  better,  thereby  securing  more  perfect  work. 

The  space  between  the  circle  and  verniers  must  be  very  small  if  an  accurate 
reading  is  to  be  obtained;  it  must  appear  through  a  reading  glass  like  a  very  fine 
black  and  uniform  line,  and  should  remain  so  during  the  revolution  of  the  circle. 

In  second-class  instruments  it  is  generally  found  that  the  verniers  and  circles 
are  not  set  in  the  same  plane;  this  is  done  to  make  any  unevenness  in  the  plate  dis- 
appear, but  it  is  a  very  objectionable  feature,  for  it  will  cause  parallax,  and  no 
accurate  reading  can  be  taken  with  such  circles. 

The  Telescope. — The  telescope  forms  a  very  important  part  of  an  instrument, 
and  must,  therefore,  be  closely  examined.  The  reason  why  so  many  telescopes  of 
second-class  instruments  are  called  good  is  because  they  have  a  very  low  magnifying 
power,  and  consequently  will  give  a  good  definition;  but  if  the  magnifying  power  of 
such  telescopes  were  to  be  increased  to  what  it  should  be,  with  the  same  kind  of 
glasses  and  workmanship,  the  definition  would  be  entirely  lost.  Experience  has 


THE    A.    LIETZ    COMPANY.  101 

shown  that  a  telescope  of  11£  inches  length,  such  as  is  generally  used  in  transits  of 
the  ordinary  size,  may  have  a  magnifying  power  of  twenty-four  diameters,  and 
give  a  good  definition  and  sufficient  light,  if  the  new  Jena  glass  is  used;  while  most 
telescopes  of  the  same  size,  which  I  have  had  occasion  to  examine,  show,  on  an  av- 
erage, a  magnifying  power  of  fifteen  diameters  only.  It  is  true  that  a  low  power 
may  be  of  advantage  under  certain  atmospherical  conditions,  but,  as  a  rule,. a  higher 
power  will  give  better  satisfaction  if  the  lenses  are  first-class. 

Inverting  telescopes,  which  are  used  almost  exclusively  in  European  countries, 
are  comparatively  little  in  vogue  in  the  American  engineering  fraternity.  They  have 
a  great  advantage  over  the  erect  telescopes;  the  eye-piece  having  two  lenses  only  and 
being  shorter,  the  proportion  between  the  focal  lengths  of  the  objective  lens  and  the 
eye-piece  may  be  increased  considerably,  and  thusly  the  magnifying  power,  without 
loss  of  light. 

Construction. — In  regard  to  the  construction,  it  is  the  aim  of  every  maker  to 
build  an  instrument  of  the  least  weight,  it  being  limited  only  to  the  extent  that  it 
shall  not  be  affected  by  the  wind  and  become  unsteady  by  reason  of  its  lightness. 
While  it  is  reasonable  that  a  proper  reduction  can  best  be  effected  by  decreasing  the 
size  of  the  whole  instrument,  instead  of  reducing  the  weight  of  individual  parts  of 
a  large  transit,  for  instance,  great  possibilities  in  this  direction  are  open  by  a  ju- 
dicious use  of  aluminium  in  the  manufacture  of  instruments.  The  author  firmly 
believes  that  with  this  metal  we  shall  be  able  to  reduce  the  weight  considerably 
without  any  sacrifice  of  steadiness,  and  it  is  his  purpose  to  make  some  detailed  in- 
vestigations in  the  near  future  that  shall  lead  to  an  intelligent  understanding  of 
this  subject. 

The  steadiness  of  an  instrument  depends  upon  its  construction;  those  that 
have  the  longest  centers,  with  the  shortest  distance  between  the  tripod-head  and 
the  plates,  and  in  which  the  distance  between  the  leveling  screws  is  large  enough  to 
secure  a  proper  base,  or,  in  other  words,  a  strong  foundation,  will  prove  to  be  firm 
and  steady  even  in.  a  strong  wind. 

The  methods  of  placing  the  verniers  of  a  transit  in  such  a  position  that  they 
may  be  read  without  stepping  aside  while  observing,  is  a  feature  in  constiuctiou 
which  has  been  pronounced  objectionable,  because  the  size  of  the  plate  level,  which 
is  at  right-angles  to  the  line  of  collimatiou,  and  which  is  the  more  important  of  the 
two,  has  to  be  reduced.  The  manner  in.  which  this  can  be  overcome  withoTit 
reducing  its  length,  or  without  placing  it  over  one  of  the  verniers  (which  must 
affect  the  degree  of  accuracy  of  the  leading  considerably),  and  the  way  in  which 
this  level  may  be  set  without  allowing  it  to  extend  beyond  the  circumference  of 
the  plate,  will  be  explained  on  some  other  occasion. 

The  Comj)ci^s. — The  compass  should  be  made  as  large  as  possible,  but  without 
reducing  the  value  of  more  important  parts.  It  can  often  be  noticed  that  an  instru- 
ment with  very  large  compass  has  the  telescope  standards  fastened  too  far  from 
the  center,  which  reduces  steadiness;  while  others,  of  course  still  worse,  have  much 
spare  room  between  standards  and  compass  box.  The  point  of  the  center-pin,  as 
well  as  the  upper  ends  of  the  needle,  must  lie  in  the  same  plane  with  the  gradua- 
tion, if  the  quivering  motion  which  most  sensitive  needles  possess,  shall  not  be 
noticed  on.  the  reading  points.  As  the  accuracy  depends  principally  on  the  pin  and 
cap,  these  should  consist  of  the  best  material,  while  the  lift  arrangement  must  be 
constructed  in  such  a  manner  as  to  raise  and  lower  the  needle  gently,  in  order  to 
prevent  the  sudden  jerking  and  falling,  which  is  so  often  the  cause  for  the  rapid 
wearing  out  of  the  point  and  cap. 


102  MODERN    SURVEYING    INSTRUMENTS, 

Other  Details. — It  is  an  important  feature  of  most  all  of  the  later  instruments 
that  the  clamp  by  which  the  horizontal  circle  is  held  in  position  works  toward  the 
center  on  a  collar,  instead  of  being  clamped  on  the  circumference  of  the  plate,  and 
that  all  tangent  screws  are  provided  with  opposing  springs. 

It  is  also  important  that  the  telescope  standards  have  bases  large  enough  to 
secure  proper  connections  with  the  plate.  It  is,  furthermore,  of  great  importance 
to  insure  steadiness  that  the  lower  parts  containing  the  leveling  screws  be  made  out 
of  one  solid  star- shaped  casting,  instead  of  the  common  round  plates  into  which 
the  nuts  are  simply  stuck  There  seems  to  be  no  other  reason  for  making  this  lat- 
ter style  than  to  save  a  few  dollars  in  labor. 

If  the  star-shaped  piece  is  slotted  and  provided  with  clamp  screws,  lost  motion, 
which  is  liable  to  appear  in  time  in  the  leveling  screws,  can  be  taken  up. 

It  goes  without  saying  that  all  transit  instruments  should  be  provided  with 
shifting  centers,  that  ought  to  be  protected  by  a  thin  metal  plate,  to  keep  the 
dust  out.  ^ 

The  Tripod.— The  tripod  legs  must  be  light  and  strong,  and  of  good  hard 
wood,  in  order  to  secure  steadiness,  and  should  be  fitted  from  the  outside,  so  that 
any  shrinkage  of  the  wood  may  be  drawn  up  by  a  nut  at  any  time.  In  the  older 
style,  where  the  legs  fit  inside,  this  cannot  be  accomplished,  and  in  that  case  it  not 
only  reduces  the  steadiness,  but  may  also  lead  to  serious  accidents.  The  split  or 
skeleton  legs  are  best  suited  to  come  up  to  all  the  requirements  of  a  good  tripod. 

The  Case. — The  manner  in  which  an  instrument  is  packed  in  its  case  is  by  no 
means  unimportant.  A  transit  must  stand  upright,  so  that  it  may  be  taken  out  by 
holding  the  lower  base-plates  and  leveling  screws,  and  not  the  upper  plates  or  the 
telescope  axis.  A  Y- level  box  should  be  provided  with  an  extra  space  for  the  tele- 
scope to  rest  in  upon  its  collars. 

The  finish. — The  outer  finish  of  an  instrument,  although  having  little  to  do  with 
its  accuracy,  will  always  be  found  of  some  elegance  in  a  first-class  article.  Un- 
fortunately, most  of  the  second-class  possess  a  brilliant  finish  that  only  too  often 
leads  purchasers  to  overlook  the  more  important  parts.  If  engineers,  when  select- 
ing instruments,  would  thoroughly  test  the  finer  qualities,  and  take  into  con- 
sideration the  construction,  they  would  not  only  be  certain  to  get  a  more  perfect 
article,  but  would  induce  makers  to  construct  and  build  instruments  in  accordance 
with  scientific  principles. 

DISCUSSION 
BY  MR.  LUTHER  WAGONER. 

The  paper  is  a  good  practical  resume  of  the  principal  points  concerning  the 
working  qualities  of  a  field  instrument,  and  I  presume  it  refers  solely  to  the  selec- 
tion of  a  new  article. 

My  experience  is  that  instruments  do  not  often  retain  the  good  points  shown  in 
the  shop  after  the  ordinary  usage  and  almost  inevitable  rough  handling  in  the  field 
and  especially  in  transportation. 

These  injuries  are  usually  springing  or  bending  of  the  centers  and  eccentricity; 
that  is,  the  two  axes  are  not  co-incident,  and  the  latter  condition  is  one  common  to 
nearly  all  instruments  in  a  greater  or  less  degree.  I  have  seen  it  large  enough  to 
cause  an  error  of  three  minutes  in  a  right-angle. 

As  it  may  be  necessary  to  try  to  do  good  work  with  such  an  instrument,  I  will 
explain  my  method  of  examining  an  instrument  having  two  verniers. 


THE    A.     LIETZ    COMPANY. 


103 


Set  one  vernier  at  zero  and  read  the  other,  calling  less  than  180  degrees  minus 
and  more  than  180  degrees  plus;  take  such  readings,  say,  every  15  degrees  on  the 
circle  and  tabulate  them  properly.  The  mean  of  all  the  readings  will  be  the  angular 


difference  of  the  verniers  from  180  degrees;  subtract  this  mean  quantity  from  each 
of  the  original  readings  (having  due  regard  to  the  algebraic  signs),  and  then  use  the 
resultant  new  column,  as  follows: 

With  any  convenient  radius  draw  a  circle  on  a  cardboard  and  divide  the  circle 
into  as  many  parts  as  there  are  observations,  numbering  the  card  like  the  instru- 
ment; then  using  the  circle  as  a  base-line,  plot  the  resultant  new  column,  calling 
inside  radical  lines  minus  and  outside  radical  lines  jilus,  using  any  convenient  scale? 
join  the  points  thus  plotted,  and  cut  out  with  a  sharp  knife  the  resultant  figure,  as 
shown  in  the  accompanying  engraving  by  shaded  lines;  balance  it  over  a  knife-edge 
in  two  or  more  positions,  and  mark  the  center  of  gravity  thus  found.  Replace  the 
figure  in  the  cardboard,  and  with  the  original  radius  and  center  of  gravity  as  a  new 
center  draw  a  circle.  (See  figure.)  The  variations  from  this  new  circle  are  the 
residual  errors  due  to  graduation  and  observation. 

Unless  an  instrument  was  either  very  poor  originally,  or  has  been  very  roughly 
handled,  these  residuals  should  not  exceed  a  few  seconds. 

The  center  of  gravity  found  by  the  above  method  is  the  vernier-plate  axis;  its 
distance  from  the  original  center  is  the  amount  of  eccentricity  measured  by  the 
scale  used  for  plotting  the  figure,  and  a  line  drawn  through  the  two  axes  gives  its 
direction. 


No. 


THE  GOLDSCHMID  ANEROID. 


It  need  hardly  be  stated  that  all  aneroid  barometers  make  use  of  the  elasticity 
of  a  hermetically  sealed  box,  or  other  closed  compartment  in  which  a  partial  vacuum 
has  been  established,  to  measure  changes  in  atmospheric  pressure.  The  movements 
of  the  box,  always  small,  are  magnified  by  means  of  a  somewhat  complex  system  of 
delicate  levers  in  the  ordinary  aneroid  forms,  of  which  that  of  Naudet's  make  may 
be  taken  as  a  type.  The  extreme  delicacy  of  the  intermediate  transmission  has 
always  proved  the  objectionable  feature  and  the  main  source  of  inaccuracy,  and  it 
was  with  the  object  of  totally  suppressing  this  transmission  that  Goldschmid  suc- 
cessively designed  the  series  of  instruments  which  bear  his  name. 

The  movements  of  the  vacuum  box  were  observed  either  by  a  micrometer  screw 
or,  as  in  the  Goldschmid-Weilenmann's  aneroid,  several  boxes  are  mounted,  one 
upon  another,  the  upper  end  of  the  series  carrying  an  index,  whose  motion  is  ob- 
served by  a  minute  telescope  provided  with  cross-hairs,  and  mounted  upon  a 
micrometer  screw. 

The  original  instrument  with  a  single  box  proved  deficient  in  delicacy,  and  the 
compound-box  aneroid  disappointed  the  expectations  of  its  designers  in  not  pos- 
sessing the  requisite  qualities  of  standing  ordinary  rough  handling  in  shipment  or 
field  use.  While  giving  admirable  results  when  left  stationary  or  carefully  carried 
upon  an  observer's  person,  curiously  enough  this  compound-box  aneroid  (No.  3) 
showed  that  sudden  jars  produced  very  considerable  changes  in  the  instrument  — 
not  abrupt  changes  only,  but  changes  such  that  often  weeks  and  months  were  re- 
quired before  the  boxes  again  assumed  a  state  of  equilibrium.  This  deficiency  was 
all  the  more  surprising  on  account  of  the  construction  having  been  so  simple,  and 
all  intermediate  transmission  having  been  eliminated,  that  special  freedom  from 
liability  to  disarrangement  had  been  confidently  anticipated. 

Since  Goldschmid's  death  his  successor,  Hottinger,  of  Zurich,  has  continued  his 
investigations,  and,  after  many  modifications  and  changes,  has  produced  the  type 
of  instruments  shown  in  figures  1,  2  and  3,  known  as  the  Goldschmid  Aneroid  No.  1. 
The  vacuum,  b  b  (Figs.  1  and  2),  is  kept  in  tension  by  the  steel  spring,//;  this 
transfers  the  movement  of  the  box-center  to  the  lever,  h  h,  turning  on  the  fulcrum, 
a.  To  the  top  of  this  lever,  h  h,  is  attached  a  hair-spring,  e  e.  The  movements  of 
the  box  are  measured  by  means  of  a  micrometer  screw,  M,  whose  contact  with  the 
hair-spring,  e  e,  must  be  ascertained  with  greater  accuracy  than  is  possible  by  the 
mere  sense  of  touch,  and  is  accordingly  indicated  by  the  coincidence  of  two  black 
lines  on  the  heads  of  the  lever,  h  A,  and  the  hair-spring,  e  et  observed  by  means  of 
a  magnifying  glass,  L.  The  scale,  S  S  (Fig.  3),  gives  the  full  revolution  of  the 
micrometer  screw.  The  first  instruments  of  this  class  were  provided  with  a  scale 
on  which  the  readings  increased  with  the  altitude,  the  value  of  the  scale-iinit  being 
arbitrary  The  scale  of  the  more  recent  instruments  is  divided  to  correspond  with 

*  From  Specht's  description  of  the  instrument  and  from  Hottinger's  illustrations. 


Fig.3 


106  THE    A.    LIETZ    COMPANY. 

the  mercurial  barometer.  Each  revolution  of  the  micrometer  screw  corresponds  to 
10  inm.  of  the  mercury  column,  and  the  head  of  the  micrometer  screw  is  decimally 
graduated,  admitting  of  accurate  reading  to  the  one-hundredth  part  of  a  millimeter. 

The  usual  size  of  this  instrument  is  3|  inches  diameter  and  2£  inches  high. 
Fig.  1  is  a  vertical  section;  Fig.  2,  a  top  view,  the  cover  being  removed;  Fig.  3,  a 
side  view;  g  y  is  the  outer  shell;  r  r  the  revolving  and  graduated  head;  h' ',  Fig.  1,  the 
end  of  the  main  lever,  and  e'  that  of  the  hair-spring  lever,  each  provided  with  an 
index-line;  £  S,  Fig.  3,  the  scale  by  which  the  number  of  full  revolutions  of  the 
micrometer  screw,  M,  Fig.  1,  are  measured. 

New  aneroids  give  elevations  at  the  ordinary  atmospheric  pressure  (25  to  30 
inches)  correctly  within  one-half  of  one  per  cent.,  the  difference  of  elevation  not 
being  more  than  750  to  1,000  feet.  For  the  determination  of  greater  differences  of 
elevation  old  aneroids  should  be  used,  in  which  the  box  has  attained  its  equilibrium. 
Indeed,  it  may  be  said  that  the  instruments  improve  with  age. 

The  influence  of  temperature  upon  44  of  these  aneroids,  tested  for  a  period  of 
six  months,  at  temperatures  of  10°  to  30°  C.  (50°  to  86°  Fahr.),  was  only  0.4  mm.  per 
1°  C. 

Each  instrument  is  provided  with  a  table  of  reduction,  giving  the  value  of  its 
unit  at  different  atmospheric  pressures  in  millimeters,  or  inches  of  the  mercurial 
barometer,  and  its  value  in  inches  or  feet,  and  the  corrections  for  temperature. 
Each  is  rated  individually  and  tested  daily  for  four  months  at  the  factory  before  be- 
ing sent  out.  No.  2  differs  slightly  from  No.  1  in  construction;  is  considerably 
smaller,  and  less  sensitive,  and  is  better  adapted  for  tourists  than  for  engineers.  Its 
probable  error  is  nearly  double  that  of  No.  1. 

In  the  aneroid  No.  3  (Weilenmanii's  system),  the  small  telescope  already  referred 
to  is  mounted  upon  a  micrometer  screw,  which  measures  its  movement.  The 
cross-hairs  of  the  telescope  being  brought  into  coincidence  with  the  index  on  the 
upper  of  the  combined  series  of  boxes,  the  scale  of  the  micrometer  indicates  directly 
the  motion  of  the  boxes  in  terms  corresponding  to  the  movements  of  the  mercurial 
barometer. 

The  boxes  are  entirely  independent  of  the  micrometer  screw,  so  that  no  changes 
in  the  instrument  can  occur  by  reason  of  wear  on  the  point  of  the  micrometer,  or 
.any  other  part.  Its  accuracy  is  so  great  that  it  can  fully  replace  the  mercury  bar- 
ometer at  atmospheric  pressure  below  24  inches,  and  it  is  much  more  portable.  Its 
size  is  6  inches  high  by  3  inches  diameter. 

Self-Registering  Aneroid  or  Barograph. 

The  purpose  of  this  instrument  is  to  register  automatically  the  readings  of  the 
.aneroid,  which  consists  of  a  number  of  boxes  like  the  one  just  described,  the  move- 
ments being  transferred  by  a  lever  to  a  paper  on  a  drum  revolved  by  clock-work. 
Every  hour  a  point  is  marked  upon  this  paper,  giving  the  reading  of  the  aneroid. 
After  48  hours  a  paper  3  inches  long  is  unwrapped,  containing  48  equidistant  points 
\\  mm.  apart.  The  dimensions  of  this  instrument  are  such  that  the  maximum 
motion  of  the  pointer  is  2  inches,  corresponding  to  the  same  movement  of  the  mer- 
curial barometer.  Two-tenths  of  a  millimeter  can  be  read  with  certainty. 


No.    5. 

A   SHORT  AND    PRACTICAL   METHOD 

To  find  the  length  of  one  minute  of  Longitude  in  any  Latitude, 

based  upon  certain  Developments  of  the  Terrestrial  Spheroid. 

By  OTTO  VON  GELDERN. 


For  the  determination  of  arcs  of  the  Parallel  and  Meridional  arcs,  certain  ele- 
ments of  the  terrestrial  spheroid  have  been  used. 

Up  to  within  the  last  ten  or  fifteen  years,  Bessel's  determinations  of  the  earth's 
magnitude  were  employed,  which  were: 

Equatorial  Radius,  a  =  6,377,397  meters, 
Polar  Radius,      .      b  =  6,356,079  meters. 

Compression  = 

299.153 

Upon  these  elements  the  usual  tables  for  the  polyconic  projection  of  maps  were 
based,  until  those  of  Col.  A.  R.  Clarke,  R.  E.,  were  adopted,  which  furnish  results 
more  in  harmony  with  recent  geodetic  measurements.  Colonel  Clarke's  researches 
were  published  in  his  Comparison  of  the  Standards  of  Length  of  England,  France, 
Belgium,  Prussia,  Russia,  India  and  Australia,  made  at  the  Ordnance  Survey  Office, 
Southampton,  1866. 

The  U.  S.  Coast  and  Geodetic  Survey  has  adopted  the  Clarke  form,  and  pub- 
lished a  long  and  carefully  computed  series  of  polyconic  projection  tables  for  it  in 
1884,  which  are  still  in  use.  (See  Appendix  No.  6,  Report  1884.) 

Limiting  the  figure  to  that  of  an  ellipsoid  of  revolution,  Clarke's  values  are: 
a  —  6,378,206  meters, 

exceeding  Bessel's     809 ™ 
b  =  6,356,584  meters, 

exceeding  Bessel's     505  m- 

Compression 

294.98 

It  shows  that  this  spheroid  is  somewhat  larger  than  Bessel's  and  that  the  eccen- 
tricity is  also  greater. 

These  elements  have  satisfied  the  conditions  developed  during  scientific  meas- 
urements of  large  areas,  so  that  they  may  be  safely  adopted  without  fear  of  appreci- 
able error. 

It  is  not  the  present  purpose  to  enter  into  the  subject  mathematically. 

If  the  earth  were  a  perfect  sphere  with  a  radius  /?,  the  expression  for  the  value 
of  one  minute  of  longitude  in  any  latitude  would  be 

coslat.       2R7r 
360  X  60 

Assuming  R  equal  to  the  length  of  the  equatorial  radius,  6,378,  206  meters,  the 
constant  1855.3  is  obtained  for  the  second  member.     By  this  constant  the  cosine  of 
the  latitude  would  have  to  be  multiplied,  in  order  to  determine  the  length  of  one 
minute  of  longitude  in  meters.     Or  logarithmically  expressed  it  is: 
log.  cos  lat.  +  3.2684256. 

As  we  are  dealing  with  a  compression  of  nearly        _  however,  it  becomes  iieces- 

oUU 


108  THE    A.    LIETZ    COMPANY. 

sary  to  take  some  recognition  of  this  fact  in  the  determination  of  distances  on  the 
parallel.  For  our  present  pin-pose  it  will  answer  if  we  find  a  method  that  shall 
furnish  results  approaching  the  truth  within  reasonably  narrow  limits,  without 
considering  exact  mathematical  formulae  for  obtaining  very  great  precision. 

After  a  careful  study  of  this  subject,  based  upon  comparisons  with  very  exact 
tabular  values,  the  following  method  is  proposed  by  the  author,  who  has  had  occa- 
sion to  make  frequent  use  of  it. 

APPROXIMATE    METHOD. 

If  the  length  of  one  minute  of  arc  on  the  parallel  be  required,  that  shall  not 
vary  greatly  from  the  correct  value,  observe  the  following  rule: 

To  the  logarithmic  constant  3.2684256  add  the  logarithmic  cosine  of  any  given 
latitude  less  5  minutes,  and  the  result  will  be  the  length  in  meters  of  one  minute  of 
longitude  in  the  given  latitude. 

Example: — What  is  the  length  of  one  minute  of  longitude  in  latitude  37°  47'  ? 

Log.  constant,         .         .         .3.2684256 

Log.  cosine  of  latitude  37*  42'  9.8982992 

(37°  47'  _  05  =37°  49')  3.1667248 

Answer,  1468.0  meters. 

(Correct  within  0.  2m.) 

By  this  method  results  are  obtained  correct  within  0.  3m'  from  the  equator  up 
latitude  60°;  from  60°  to  70°  within  0.  5 ^  ;  beyond  that  limit  the  deviations  from 
the  true  values  grow  more  rapidly,  yet  even  at  80°  a  minute  of  longitude  thus  ob- 
tained would  have  an  excess  of  1.  6m-  only.  For  all  ordinary  requirements,  there- 
fore, the  above  rule  will  apply. 

A  deduction  of  an  even  5  minutes  gives  the  best  average  results,  and  for  that  rea- 
son it  has  been  adopted.  If  we  want  to  be  a  little  more  precise  about  it,  we  may 
use  4  minutes  from  0  to  latitude  25°,  and  from  65°  upwards;  5  minutes  from  25°  to 
35°,  and  from  50°  to  65°;  and  6  minutes  from  35°  to  50°.  With  this  precaution  the 
results  will  not  vary  more  than  0.  2m-  for  any  case  from  the  equator  up  to  latitude 
70°. 

If  the  distance  is  desired  in  feet  instead  of  meters,  multiply  the  result  by  3  28087, 
or  use  the  logarithmic  constant  3.7844146  instead  of  the  one  given  above 

A    MORE    ACCURATE     METHOD. 

Where  greater  refinement  is  required,  say  that  instead  of  one  minute  we  should 
want  the  length  of  one  degree  of  arc  without  appreciable  error,  the  deductions  from 
the  latitude  must  be  defined  a  little  more  closely  still,  if  they  shall  furnish  re^able 
results. 

By  using  the  deductions  given  in  minutes  and  seconds  in  the  table  below,  for 
every  5°  of  latitude,  results  may  be  obtained  that  will  be  without  appreciable  devi- 
ation from  the  truth,  even  in  the  case  of  the  length  of  one  degree  on  a  parallel. 

In  latitude       0°     deduct     0'     0".  In  latitude     45°     deduct     5'  50'. 

5°         ••  V  00'.  "         "          50°         "  5'  40'. 

10°         "  I'  50'.  "         "          55^         "  5'  30'. 

15°         "  2'  40".  "         •'  60°         "  5'  00'. 

20=         «          3'  50-  .,         „  65o         ,.          4,  3(r 

25°  "  4'  30".  "  "  70°  "  3'  50'. 

30°  "  5'  00'.  "  «  75°  "  3'  00'. 

35°  "  5'  30'.  "  »  80°  ••  2'  00'. 

40°  "  5'  40'. 


MODERN    SURVEYING    INSTRUMENTS,  109 

Any  intermediate  value  may  be  interpolated. 

Referring  again  to  the  previous  example,  let  us  find  the  value  of  one  minute  of 
longitude  in  latitude  37°  47'  by  this  method. 

By  consulting  our  table  we  find  that  for  37°  47'  we  must  deduct  5'  35",  leaving 
37°  41' 25'.  Then  write: 

Log.  constant,         ....     3.2684256 
Log.  cosine  of  latitude  37°  41'  25',     9.8983724 

3.1667980 
Answer,  .  .....      1468.2  meters. 

(Which  is  correct  to  the  nearest  tenth.) 

If  the  length  of  a  degree  is  wanted,  multiply  the  result  by  60,  or  use  the  con- 
stant 5. 0465769  instead  of  the  one  above  given. 

Example: — What  is  the  length  of  one  degree  of  longitude  in  latitude  17°? 

Log.  constant,         .  5.0465769 

Log.  cosine  16°  56'  45",     9.9807216 

(17°  —  3'  15")  5.027298~5 

Answer,  .......    106,487  meters. 

(Which  is  correct  to  the  nearest  meter.) 
Again,  for  latitude  74°? 

Log.  constant,         .  5,0465769 

Log.  cosine  73°  56'  50',     9.4417308 

4.48S3077 
Answer,  .  .....      30,782  meters. 

(Correct  within  1  meter.) 

These  results  are  readily  reduced  to  either  nautical  or  statute  miles,  by  dividing 
by  1853.248  (log.  3.2679335)  in  the  former,  and  by  1609.33  (log.  3.2066449)  in  the 
latter  case.  The  logarithmic  constant  may  be  changed  to  suit  these  measures 

THE    NAUTICAL    MILE. 

The  length  of  a  nautical  mile  has  been  adopted  at  1853.248  meters,  or  6080.27 
feet.  It  will  be  noticed  that  this  is  2.1  meters  less  than  the  length  of  one  minute  of 
longitude  at  the  equator,  which  is  ordinarily  assumed  as  that  which  defines  the 
nautical  mile.  The  tact  is  that  this  unit  of  measure  has  been  arbitrarily  based,  and 
that  it  varies  as  the  data  from  which  the  deductions  are  made.  In  order  to  estab- 
lish uniformity  for  all  time,  the  nautical  mile  is  now  denned  as  the  length  of  one 
minute  of  a  great  circle  of  a  sphere  that  shall  have  the  same  superficial  area  as  the 
terrestrial  spheroid.  This  basis  was  adopted  by  the  U.  S.  Coast  and  Geodetic  Sur- 
vey, and  computed  from  Clarke's  elements. 


Length  of  One  Minute  of  Latitude  in  Different  Latitudes. 


At  the  Equator,       .         .  1842.8  meters  At  50°,  .         .         .  1853.8  meters 

"  10%         .         .         .  1843.4       "  "  60%  ....  1856.9      " 

"  2& 1845.0       "  "  70%  .         .        .  1859.4      «• 

"  30',         .         .         .  1847.5       "  "  80%  ....  1861.1      " 

"  40°,                                .  1850.5       "  "  90°,  .         .         ,  1861.7      " 


Ko.   6. 


THE 
SAEGMULLER  SOLAR  ATTACHMENT 


VERTICAL  SIGHTING  TELESCOPE. 

(Patented  May  3,  iSSi.) 

How  TO  ADJUST  AND  USE  IT,  WITH  REFRACTION  TABLES. 


THE  A.  LIETZ  COMPANY, 

Sole  Agents  on  the  Pacific  Coast  of  the  Saegmiiller  Solar. 
SAN  FRANCISCO,  CAL.,  1803 


This  attachment  to  the  regular  engineer's  transit,  by  means  of  which  the  astro- 
nomical meridian  may  be  obtained  in  a  few  minutes  with  an  accuracy  scarcely  thought 
to  be  possible,  has  met  with  such  success  that  it  bids  fair  to  supersede  all  other 
methods  for  the  determination  of  the  meridian  by  means  of  engineering  instruments. 

The  transit  has  come  to  be  the  universal  instrument  for  the  engineer,  and  will 
be  for  the  surveyor  sooner  or  later,  and  the  attachment  of  the  solar  apparatus  to  the 
transit  has  thus  become  a  necessity. 

Since  its  first  introduction  this  attachment  has  been  greatly  improved,  and,  as 
now  made,  is  nearly  perfect. 

Attached  to  any  transit  which  possesses  a  telescope,  level  and  a  vertical  circle,  it 
will  give  the  meridian  within  the  nearest  minute.  By  using  instruments  which  have 
a  finer  graduated  vertical  circle  and  better  levels  than  are  usually  found  on  transits, 
the  meridian  can  be  determined  with  greater  accuracy  still. 

Advantages  of  the  "Saegmuller  Solar  Attachment"  over  the  Old  Form. 

First — It  is  more  accurate. 

Second. — It  is  simpler  and  easier  of  adjustment. 

Third. — It  can  be  Tised  when  the  sun  is  partly  obscured  by  clouds,  when  ihe 
ordinary  "solar  "  fails  altogether. 

Fourth. — It  can  be  used  where  the  sun  is  quite  close  to  the  meridian. 

Fifth. — The  time  can  be  obtained  with  it  reliable  to  within  a  few  seconds  with 
perfect  ease. 

Sixth. — It  can  be  used  as  a  vertical  sighting  telescope. 

It  is  as  superior  to  all  forms  hitherto  used  as  the  transit  is  to  the  ordinary  com- 
pass, or  as  a  telescope  is  to  common  sights. 

*  Reprinted  by  permission,  ami  revised  tor  this  Manual 


MODERN  SURVEYING  INSTRUMENTS, 

The  sights  of  an  ordinary  solar  compass  consist  merely  of  a  small  lens  and  a 
piece  of  silver  with  lines  ruled  on  it  placed  in  its  focus.  This  is  simply  a  very 
primitive  telescope,  since  the  exact  coincidence  of  the  sun's  image  with  the  lines 
has  to  be  determined  by  the  unaided  eye,  or  at  best  with  a  simple  magnifying  glass. 

That  far  greater  precision  can  be  attained  by  means  of  a  suitable  telescope  is 
obvious;  in  fact,  the  power  of  the  solar  telescope  is  in  keeping  with  the  transit  tel- 
escope, as  it  should  be. 

A  glance  at  the  illustration  will  show  that  the  "Saegmuller  Solar  Attachment  " 
is  far  simpler  than  the  ordinary  form.  By  raising  or  depressing,  it  can  be  set  to 
north  or  south  declination.  To  effect  this  with  the  ordinary  solar  compass  two  sets 
of  primitive  telescopes  —  one  answering  for  north,  the  other  for  south  declination  — 
are  required,  which  are  difficult  to  adjust. 

The  addition  of  the  level  on  the  solar  telescope  dispenses  with  the  declination 
arc  altogether,  the  arc  or  circle  on  the  transit  also  serving  for  that  purpose  in  con- 
junction with  it. 

The  "Saegmuller  Solar  Attachment  "  is,  in  fact,  the  only  one  which  should  be 
used  in  connection  with  a  transit  instrument.  It  solves  the  solar  problem,  as  has 
been  attested  by  leading  astronomers  and  engineers  who  have  used  it. 

Professor  J.  B.  Johnson,  of  Washington  University,  St.  Louis,  Mo.,  has  given 
it  a  thorough  test,  and  writes  as  follows: 

"  In  order  to  determine  just  what  accuracy  was  possible  with  a  Saegmuller  Solar 
Attachment,  I  spent  two  days  in  making  observations  on  a  line  whose  azimuth  had 
been  determined  by  observations  on  two  nights  on  Polaris  at  elongation,  the  instru- 
ment being  reversed  to  eliminate  errors  of  adjustment.  Forty-five  observations 
were  made  with  the  solar  attachment  on  October  24,  1885,  from  9  to  10A.M.,  and 
from  1:30  to  4  P.  M.,  and  on  November  7,  forty-two  observations  between  the  same 
hours. 

' '  On  the  first  day's  work  the  latitude  used  was  that  obtained  by  an  observation 
on  the  sun  at  its  meridian  passage,  being  38°  39',  and  the  mean  azimuth  was  20 
seconds  in  error.  On  the  second  day,  the  instrument  having  been  more  carefully 
adjusted,  the  latitude  used  was  38°  37',  which  was  supposed  to  be  about  the  true 
latitude  of  the  point  of  observation,  which  was  the  corner  of  Park  and  Jefferson 
avenues  in  this  city.  It  was  afterwards  found  that  this  latitude  was  38°  37'  15",  as 
referred  to  Washington  University  Observatory,  so  that  when  the  mean  azimuth  of 
the  line  was  corrected  for  this  15"  error  in  latitude,  it  agreed  exactly  with  the  stellar 
azimuth  of  the  line,  which  might  have  been  10' or  15"  in  error.  On  the  first  day  all 
the  readings  were  taken  without  a  reading  glass,  there  being  four  circle  readings  to 
each  result.  On  the  second  day  a  glass  was  used. 

"  On  the  first  day  the  maximum  error  was  4  minutes,  the  average  error  was  0.8 
minute,  and  the  'probable  error  of  a  single  observation'  was  also  0.8  minute.  On 
the  second  day  the  maximum  error  was  2.7  minutes,  the  average  error  was  1  minute, 
and  the  'probable  error  of  a  single  observation'  was  0.86  minute.  The  time  re- 
quired for  a  single  observation  is  from  three  to  five  minutes. 

"  I  believe  this  accuracy  is  attainable  in  actual  practice,  as  no  greater  care  was 
taken  in  the  adjustment  or  handling  of  the  instrument  than  should  be  exercised  in 
the  field. 

"  The  transit  has  come  to  be  the  universal  instrument  for  the  engineer,  and 
should  be  for  the  surveyor;  so  it  is  more  desirable  to  have  the  solar  apparatus  at- 
tached to  the  transit  than  to  have  a  separate  instrument.  The  principal  advantages 
of  this  attachment  are: 


THE    A.    LIETZ    COMPANY. 

"  1.     Its  simplicity. 

"  2.  Its  accuracy  of  pointing,  being  furnished  with  a  telescope  which  is  accu- 
rately set  on  the  sun's  disk. 

"3.  In  its  providing  that  all  angles  be  set  off  on  the  vertical  and  horizontal 
limbs  of  the  transit,  thus  eliminating  the  eccentricity  and  other  inaccuracies  usually 
found  in  attachment  circles  or  arcs. 

"  4.     Its  small  cost. 

"  It  is  also  readily  removed  and  replaced  without  affecting  its  adjustments,  and 
is  out  of  the  way  in  handling  and  reversing  the  telescope.  It  may  be  attached  to 
any  transit." 


SAEGMULLER  SOLAR   ATTACHMENT. 

This  instrument  may  be  had  in  ALUMINIUM,  which  gives  that  lightness 
particularly  desirable  in  an  attachment  of  this  character. 

The  illustration  represents  the  improved  "  Saegmiiller  Solar  Attachment  "  as  now 
made.  It  consists  essentially  of  a  small  telescope  and  level,  the  telescope  being 
mounted  in  standards,  in  which  it  can  be  elevated  or  depressed.  The  standard  re- 
volves around  an  axis,  called  the  polar  axis,  which  is  fastened  to  the  telescope  axis 
of  the  transit  instrument.  The  telescope,  called  the  "  Solar  Telescope,"  can  thus  be 
moved  in  altitude  and  azimuth.  Two  pointers  attached  to  the  telescope  to  approx- 
imately set  the  instrument,  are  so  adjusted  that  when  the  shadow  .of  the  one  is 
thrown  on  the  other  the  sun  will  appear  in  the  field  of  view. 

ADJUSTMENT  OF  THE  APPARATUS. 

1.  The  transit  must  be  in  perfect  adjustment,  especially  the  levels  on  the  tele- 
scope and  the  plates;  the  cross-axis  of  the  telescope  should  be  exactly  horizontal, 
and  the  index  error  of  the  vertical  circle  carefully  determined. 

2.    The  polar  axis  must  be  at  right-angles  to  the  line  of  collimation  and 
horizontal  axis  of  main  telescope. 

To  effect  this,  level  the  instrument  carefully  and  bring  the  bubble  of  each  tele- 
scope level  to  the  middle  of  its  scale.  Revolve  the  solar  around  its  polar  axis,  and 


MODERN    SURVEYING    INSTRUMENTS. 

if  the  bubble  remain  central,  the  adjustment  is  complete.  If  not,  correct  half  the 
movement  by  the  adjusting  screws  at  the  base  of  the  polar  axis,  and  the  other  half 
by  moving  the  solar  telescope  on  its  horizontal  axis. 

3.    The  line  of  collimation  of  the  solar  telescope  and  the  axis  of  its 
level  must  be  parallel. 

To  effect  this,  bring  both  telescopes  in  the  same  vertical  plane  and  both  bubbles 
to  the  middle  of  their  scales.  Observe  a  mark  through  the  transit  telescope,  and 
note  whether  the  solar  telescope  points  to  a  mark  above  this,  equal  to  the  distance 
between  the  horizontal  axes  of  the  two  telescopes.  If  it  does  not  bisect  this  mark, 
move  the  cross-wires  by  means  of  the  screws  until  it  does.  Generally  the  small 
level  has  no  adjustments,  and  the  parallelism  is  effected  only  by  moving  the  cross- 
hairs. 

The  adjustments  of  the  transit  and  solar  should  be  frequently  examined,  and 
kept  as  nearly  perfect  as  possible. 

DIRECTIONS    FOR    USING    THE    ATTACHMENT. 

First. — Take  the  declination  of  the  sun  as  given  in  the  Nautical  Almanac*  for 
the  given  day,  and  correct  it  for  refraction  and  hourly  change.  Incline  the  transit 
telescope  until  this  amount  is  indicated  by  its  vertical  arc.  If  the  declination  of  the 
sun  is  north,  depress  it;  if  south,  elevate  it.  Without  disturbing  the  position  of 
the  transit  telescope,  bring  the  solar  telescope  into  the  vertical  plane  of  the  large 
telescope,  and  to  a  horizontal  position  by  means  of  its  level.  The  two  telescopes 
will  then  form  an  angle  which  equals  the  amount  of  the  declination,  and  the  incli- 
nation of  the  solar  telescope  to  its  polar  axis  will  be  equal  to  the  polar  distance  of 
the  sun. 

Second. — Without  disturbing  the  relative  positions  of  the  two  telescopes,  incline 
them  and  set  the  vernier  to  the  co-latitude  of  the  place. 

By  moving  the  transit  and  the  "Solar  Attachment"  around  their  respective 
vertical  axes,  the  image  of  the  sun  will  be  brought  into  the  field  of  the  solar  tele- 
scope, and  after  accurately  bisecting  it,  the  transit  telescope  must  be  in  the  meridian, 
and  the  compass-needle  indicates  its  deviation  at  that  place. 

The  vertical  axis  of  the  "Solar  Attachment"  will  then  point  to  the  pole,  the 
apparatus  being  in  fact  a  small  equatorial. 

Time  and  azimuth  are  calculated  from  an  observed  altitude 
of  the  sun  by  solving  the  spherical  triangle  formed  by  the  sun, 
the  pole,  and  the  zenith  of  the  place.  The  three  sides,  S  P, 
P  Z,  Z  S,  complements  respectively  of  the  declination,  latitude 
and  altitude,  are  given,  and  we  hence  deduce  S  P  Z,  the  hour 
angle,  from  apparent  noon,  and  P  Z  S  the  azimuth  of  the  sun. 
The  "  Solar  Attachment  "  solves  the  same  spherical  triangle 
by  construction,  for  the  second  process  brings  the  vertical  axis 
of  the  solar  telescope  to  the  required  distance,  Z  P,  from  the 
zenith,  while  the  first  brings  it  to  the  required  distance,  S  P, 
from  the  sun. 

OBSERVATION    FOR    TIME. 

If  the  two  telescopes,  both  being  in  position  —  one  in  the  meridian,  and  the 
other  pointing  to  the  sun  —  are  now  turned  on  their  horizontal  axes,  the  vertical 

*  A  Nautical  Almanac  must  be  a  part  of  the  engineer's  field  outfit. 


114 


THE    A.     LIKTZ    COMPANY. 


remaining  undisturbed,  until  each  is  level,  the  angle  between  their  directions  (found 
by  sighting  on  a  distant  object)  is  S  P  Z,  the  time  from  apparent  noon. 

This  gives  an  easy  observation  for  correction  of  time-piece,  reliable  to  within  a 
few  seconds. 


TO    OBTAIN    THE    LATITUDE    WITH    THE 

ATTACHMENT." 


SAEGMULLER    SOLAR 


Level  the  transit  carefully  and  point  the  telescope  toward  the  south,  and  elevate 
or  depress  the  object  end,  according  as  the  declination  of  the  sun  is  south  or  north, 
an  amount  equal  to  the  declination. 

Bring  the  solar  telescope  into  the  vertical  plane  of  the  main  telescope,  level  it 
carefully  and  clarnp  it.  With  the  solar  telescope  observe  the  sun  a  few  minutes 
before  its  culmination;  bring  its  image  between  the  two  horizontal  wires  by  moving 
the  transit  telescope  in  altitude  and  azimuth,  and  keep  it  so  by  the  slow-motion 
screws  until  the  sun  ceases  to  rise.  Then  take  the  reading  of  the  vertical  arc,  cor- 
rect for  refraction  due  to  altitude  by  the  table  below.  Subtract  the  result  from  90°, 
and  the  remainder  is  the  latitude  sought. 

Mean  Refraction. 
Barometer  30  inches,  Fahrenheit  thermometer  50  degrees 


Altitude. 

Refraction. 

Altitude. 

Refraction 

10° 

5'   19' 

20^ 

2'    39' 

11 

4     51 

25 

2     04 

12 

4     27 

30 

1     41 

13 

4     07 

35 

1     23 

14 

3     49 

40 

1     09 

15 

3     34 

45 

58 

16 

3     20 

50 

49 

17 

3     08 

60 

34 

18 

2     57 

70 

21 

19 

2     48 

SO 

10 

The  following  table,  computed  by  Prof.  Johnson,  C.  E.,  Washington  University, 
St.  Louis,  will  be  found  of  considerable  value  in  solar  compass  work: 

"This  table  is  valuable  in  indicating  the  errors  to  which  the  work  is  liable  at 
different  hours  of  the  day  and  for  different  latitudes,  as  well  as  serving  to  correct 
the  observed  bearings  of  lines  when  it  afterwards  appears  that  a  wrong  latitude  or 
declination  has  been  used.  Thus  on  the  first  day's  observations  I  used  a  latitude 
in  the  forenoon  of  38°  37',  but  when  I  came  to  make  the  meridian  observation  for 
latitude  I  found  the  instrument  gave  38°  39'.  This  was  the  latitude  that  should 
have  been  used,  so  I  corrected  the  morning's  observations  for  two  minutes  error  in 
latitude  by  this  table. 

"It  is  evident  that  if  the  instrument  is  out  of  adjustment  the  latitude  found 
by  a  meridian,  observation  will  be  in  error;  but  if  this  observed  latitude  be  used  in 
setting  off  the  co-iatitude,  the  instrumental  error  is  eliminated.  Therefore,  always 


MODERN    SURVEYING    INSTRUMENTS. 


115 


use  for  the  co-latitude  that  given  by  the  instrument  itself  in  a  meridian  observa- 
tion." 

Error*  in  Azimuth  (by  Solar  Compass) for  1  Minute  Error  in  Decimation  or  Latitude. 


HOUR. 

FOR  1  MIN.  ERROR  IN  DECLINA- 
TION. 

FOR  1  MIN.  ERROR  IN  LATI- 
TUDE. 

Lat.  30° 

Lat.  40° 

Lat.  50° 

Lnt.  30° 

Lat  .  40° 

Lat.  50° 

MIX. 

MIX. 

MIX. 

MIX. 

MIX. 

MIX. 

11:30  A.  M...  1 
1-2:30  P.  M...  J 

8.85 

10.00            12.90 

8.77 

9.92 

11.80 

11    A.    M  ) 

1  r.  M.. 

4.46 
2.31 
1.63 
1.34 
1  20 

5.05 
2.61 
1.85 
1.51 
1.35 

6.0! 
3.11 
2.20 
1.80 
1.61 

4.33 
2.00 
1.15 
0.67 
0.31 

4.87 
2.26 
1.30 
0.75 
0.35 

5.80 
2.70 
1.56 
0.90 
0.37 

10  A.   M  \ 
2  P.   M  J 

9  A.M.                    1 

3  P.  M.                   J 

8  A.M...           .   \ 
4  P.  M  / 

7  A  .  M  .                    ") 

5  P.  M  J 

G  A.  M  \ 
6  P.  M  J 

1.15 

1.30 

1.56 

1 

0.00 

0.00 

0.00 

NOTE.— Azimuths  observed  with  erroneous  decimation,  or  co-latitude  may  be  corrected  by  means  of  this 
table  l>y  observing  that  for  the  line  of  collimation  set  too  high,  the  aximuth  of  any  line  from  the  south  point  in 
the  direction  of  S.  W.  N.  E.  is  found  too  small  in  the  forenoon  and  too  large  in  the  afternoon  by  the  tabular 
amounts  for  each  minute  of  error  in  the  altitude  of  the  line  of  sight.  The  reverse  is  true  for  the  line  set  too 
low. 

CORRECTION    FOR    REFRACTION. 

This  correction  is  applied  to  the  declination  of  the  sun,  and  is  equal  to  the 
refraction- correction  of  the  sun's  observed  altitude  multiplied  by  the  cosine  of  the 
angle  which  the  sun  makes  between  the  declination-circle  and  the  vertical. 

In  order  to  reduce  the  refraction  correction  to  the  simplest  possible  form,  we 
have  added  a  table  showing  the  refraction  for  every  day  of  the  year,  at  different 
hours,  for  latitude  40°,  in  5-day  periods. 

THE    PREPARATION    OF   THE    DECLINATION   SETTINGS    FOR  A  DAY'S 

WORK. 

The  Solar  Ephemeris  gives  the  declination  of  the  sun  for  the  given  day,  for 
Greenwich  mean  noon.  Since  all  points  in  America  are  west  of  Greenwich,  by  5,  6, 
7  or  8  hours,  the  declination  found  in  the  ephemeris  is  the  declination  at  the  given 
place  at  7,  6,  5  or  4  o'clock  A.  M.,  of  the  same  date,  according  as  the  place  lies  in 
the  "  Eastern,"  "  Central,"  "  Mountain  "  or  "  Western  Time  "  belts  respectively. 

The  appended,  termed  "Refraction  Correction,"  gives  the  correction  to  be 
made  to  the  declination,  for  refraction,  for  any  point  whose  latitude  is  40°.  If  the 
latitude  is  more  or  less  than  40°,  these  corrections  are  to  be  multiplied  by  the  cor- 
responding coefficients  given  in  the  table  of  "  Latitude  Coefficients."*  Thus  the 


*  This  table  just  precedes  the  "Refraction  Correction"  table,  see  following  pages. 


116 


THE    A.     LIETZ    COMPANY. 


refraction  corrections  in  latitude  30°  are  65  huiidredths,  and  those  of  50°,  142  hun- 
dredths  of  the  corresponding  ones  in  latitude  40°.  There  is  a  slight  error  in  the  uf 
of  these  latitude  coefficients,  but  the  maximum  error  will  not  amount  to  over  15", 
except  when  the  sun  is  very  near  the  horizon,  and  then  any  refraction  becomes  very 
uncertain.  All  refraction  tables  are  made  out  for  the  mean,  or  average,  refraction, 
whereas  the  actual  refraction  at  any  particular  time  and  place  may  be  not  more  than 
one-half,  or  as  much  as  twice  the  mean  refraction,  with  small  altitudes.  The  errors 
made  in  the  use  of  these  latitude  coefficients  are,  therefore,  very  small  as  compared 
with  the  errors  resulting  from  the  use  of  the  mean,  rather  than  unknown  actual 
refraction  which  affects  any  given  observation. 

Example  I. 

Let  it  be  required  to  prepare  a  table  of  decimations  for  a  point  whose  latitude 
is  38°  30',  and  which  lies  in  the  "  Central  Time  "  belt,  for  April  5,  1890. 

Since  the  time  is  6  hours  earlier  than  that  at  Greenwich,  the  declination  giveii 
in  the  ephemeris  of  the  Nautical  Almanac  is  the  declination  here  at  6  A.  M.  of  same 
date.  This  is  found  to  be  -\-  6°  9'  57".  To  this  must  be  added  the  hourly  change, 
which  is  also  plus,  and  equal  to  56 ".83.  The  latitude  coefficient  is  0.94,  and  the 
refraction  corrections  which  must  be  multiplied  by  0.94  are  found  in  our  table  for 
April  5th,  as  follows : 

1st  hour 0'  39"  X  0.94  r=  0'  37" 

2d       "      0'  44"  X  0.94 '  =  0'  41" 

3d      "      0'54"  x  0.94  =  0' 51" 

4th     "      r  14"  X  0.94  ==  V  10" 

5th    "      2'  08"  X  0.94  =  2'  00" 

The  same  corrections  apply  to  the  4th,  5th,  6th,  7th  and  8th  of  April,  but  they 
are  strictly  exact  for  the  middle  day  of  the  5-day  period  corresponding  to  that  set 
of  hourly  corrections  only.  For  the  extreme  days  of  any  such  period  an  interpo- 
lation can  be  made  between  the  adjacent  hourly  corrections,  if  desired. 

The  following  table  may  now  be  made  out: 

Declination  Settings  for  April  J,  1890,  Lat.  38°  30',  Central  Time. 


Hour. 

Declination 

Ref.  Cor.       Setting. 

Hour.            Declination. 

!               1 

Eef.  Cor. 

Setting. 

7 

+6°    10'     54" 

+2'  00"  6°  12'  54" 

1 

6°  1G'  35" 

4-     37" 

G°17'12" 

8 

G     11     51 

-hi   10  ;6  13  01 

2 

G    17  31 

+     41 

G  18  12 

9 

G     12     47 

-f     51   !6  13  38 

3 

6    18  28 

4-     51 

6  19  11) 

10 

6     ]3     44       {  -f     41    6  14  25 

4 

6    19  25 

-f  no" 

6  20  35 

11 

6     14     41 

-h     37 

G  15  13 

5 

6   20  22 

4-2  oo 

6  22  22 

Example  II. 

Let  it  be  required  to  prepare  a  declination  table  for  a  point  in  Lut.  45  ,  in  the 
"Eastern  Time"  belt,  for  October  10,  1890. 

The  time  now  is  5  hours  earlier  than  that  of  Greenwich,  hence  the  declination 
given  in  the  ephemeris  for  Greenwich  mean  noon  is  the  declination  at  our  point  at 


MODERN    SURVEYING    INSTRUMENTS. 


117 


7  A.  M.     The  declination  found  is  — 6°  43'  56',  and  the  hourly  change  is  —  56". 87. 
Our  latitude  coefficient  is  1.20. 
The  table  then  becomes: 

Declination  Settings  for  October  10,  1890,  Lat.  45°,  Eastern  Time. 


Hour 

• 

Declination. 

Ref.  Cor. 

Settings.          Hour 

Declination. 

Kef  Cor. 

Settings. 

t 

-6°  43'   56 

+    5'    35" 

—6°  38'    21" 

1 

—6°  49'   37" 

-f  r  is" 

-6°  48'  21" 

8 

—6     44    53 

-f  2     31 

—6     42     22 

0 

—6     50     34 

4-  1     24 

—6  49  10 

9 

—6     45     50 

4-  1     44 

—6     44     06 

o 

—6     51     31 

4-   1     44 

—6  49  47 

10 

-6     46     47 

4-  1     24 

—6     45     23 

4 

—6     52     28 

-f  2     31 

—6  49  57 

11 

—6     47     44 

4-  1     16 

—6     46     28 

5 

—6     53     25 

-1-  5     35 

—6  47  50 

If  the  date  be  between  June  20,  and  September  20,  the  declination  is  positive, 
and  the  hourly  change  negative;  while,  if  it  be  between  December  20,  and  March  20, 
the  declination  is  negative  and  the  hourly  change  positive.  The  refraction  correc- 
tion is  always  positive — that  is,  always  increases  numerically  the  north  declina- 
tions, and  diminishes  numerically  the  south  declinations. 

By  using  standard  time  instead  of  local  time,  a  slight  error  is  made,  but  the 
maximum  value  of  this  error  is  found  at  those  points  where  the  standard  time 
differs  from  the  local  time  by  one-half  hour,  and  in  the  spring  and  fall  when  the 
declination  is  changing  rapidly.  The  greatest  error,  then,  is  less  than  30",  and 
this  is  smaller  than  can  be  set  off  011  the  vertical  circle  or  declination  arc.  .  Even 
thi^  error  can  be  avoided  by  using  the  true  difference  of  time  from  Greenwich-  in 
place  of  the  standard  meridian  time. 

THE  SAEGMULLER  SOLAR  ATTACHMENT  WHEN  USEO  AS  A  VERTICAL 
SIGHTING    TELESCOPE. 

Although  this  attachment  is  familiar  to  every  engineer,  it  is  only  quite  recently 
that  it  has  been  recognized  as  the  best  Vertical  Sighting  Telescope  which  can  easily 
be  attached  to  the  ordinary  transit,  and  which  will  give  accurate  results. 

It  is  readily  seen  that  the  construction  of  the  attachment  allows  the  small  tele- 
scope to  be  placed  in  a  vertical  position,  and  when  so  placed,  as  represented  in  our 
illustrations  of  transits  with  solar  attachments,  it  fulfils  every  requirement  of  an 
instrument  designed  for  vertical  as  well  as  oblique  sighting  in  mining  work. 

In  order  to  use  the  solar  for  this  purpose,  proceed  as  follows: 

See  that  the  transit  is  in  perfect  adjustment.  Point  both  telescopes  horizontal 
and  see  that  the  Solar  points  as  much  above  the  transit  telescope  as  equals  the  dis. 
tance  between  their  axes.  When  this  is  the  case  the  lines  of  collimation  of  both 
tele.jcopes  are  parallel.  Now  turn  the  transit  telescope  90°,  as  shown  by  the  vertical 
circle,  taking  care  not  to  disturb  the  relative  position  of  the  solar  telescope  and 
that  of  the  transit,  and  both  will  point  vertically  downwards. 

As  the  standards  of  the  Solar  are  high  enough  to  allow  the  small  telescope  to 
clear  the  plates,  it  is  evident  that  the  solar  telescope  now  points  accurately  to  the 
Nadir. 

The  same  modus  operandi  holds  good  when  it  is  desired  to  obtain  an  oblique 
sight,  as  it  is  only  necessary  to  set  off  the  desired  slope  on  the  vertical  circle,  after 
having  both  telescopes  parallel. 


118 


THE    A.     LIETZ    COMPANY. 


For  very  accurate  work  it  is  desirable  to  make  the  observations  in  two  positions 
by  reversal.  By  taking  the  mean  of  the  two  sets  of  observations,  instrumental  errors 
are  eliminated. 

In  order  to  make  the  Saegmliller  Solar  Attachment  as  efficient  as  possible  for 
the  above  purpose,  the  size  of  the  telescope  has  been  increased,  giving  it  ample 
power  to  locate  a  point  with  great  precision. 


TABLE    OF    LATITUDE    COEFFICIENTS, 

To  be  Used  in  Connection  with  the  Refraction  Correction  Tables  for 
Latitude  4O°.     (See  the  following  pages.) 


LA?. 

COEFF. 

LAT. 

COEFF. 

LAT. 

COEFF. 

15^ 

.30 

31° 

.68 

47° 

1.29 

16 

.32 

32 

.71 

48 

1  .  33 

17 

•  .34 

33 

.75 

49 

1.38 

IS 

.36 

34 

.78 

50 

1.42 

19 

.38 

35 

.82 

51 

1.47 

20 

.40 

36 

.85 

52 

1.53 

21 

.42 

37 

.89 

53 

1.58 

22 

44 

38 

.92 

54 

1.64 

23 

• 

.46 

39 

.96 

55 

1.70 

24 

.48 

40 

1.00 

56 

1.76 

25 

.50 

41 

1.04 

57 

1.82 

26 

.53 

42 

1.08 

58 

1.88 

27 

.56 

43 

1.12 

59 

1.94 

28 

59 

44 

1.16 

60 

2.00 

29 

.62 

45 

1.20 

30 

.65 

46 

1.24 

MODERN    SURVEYING    INSTRUMENTS. 


119 


REFRACTION    CORRECTION*. 

LATITUDE  40r. 


Refrac- 

Jan. 

Refraction 
Correction 

Feb. 

Refraction 
Correction 

Mar. 

Refraction 
Correction 

Apr. 

Refraction 
Correction 

May. 

Refraction 
Correction 

June 

tion  Cor- 
rection 

Lat.  40  cleg. 

Lat  40deg. 

Lat.  40  deg. 

Lat.  40  deg. 

Lat.  40  deg,, 

.  La*. 

40  d.g. 

h.  '      " 

h.    ' 

h.    '     " 

h.  '     " 

h.'    - 

I 

1    1.58 

1 

1 

1    1.03 

1 

3  0.57 

1 

1    0.28 

1 

5  1.11 

2  2.16 

2 

2  1.10 

2 

4  1.19 

2  0.32 

2 

3  3.04 

h.  '     " 

3  1.27 

3 

5  2.18 

2 

3  0.39 

3 

4  6.23 

3 

1    1.26 

3 

4  2.06 

4  0.55 

3 

1  0.19 

4 

O     I     Q7 

4 

5  4.39 

4 

1  0.39 

3 

5  1.30 

4 

2  0.23 

4 

1     1     i4- 

5 

—    1  .  o/ 

5 

2  0.44 

5 

3  0.30 

5 

I       1  .  tJT: 

6 

3  2.04 

5 

1  0.59 

6 

3  0.54 

4 

1  0.26 

6 

4  0.43 

6 

1  2.11 

7 

4  3  21 

6 

2  1.06 

7 

4  1.14 

5 

2  0  30 

7 

5   1.10 

i 

3  2.59 

7 

3  1.21 

8 

5  2.08 

6 

3  0.37  ! 

8 

4  6.01 

0 

1   1.21 

8 

4  1.56 

7 

4  0.53 

8 

1  0.18 

o 

O    I    qi 

9 

5  4.04 

9 

1  0.36 

8 

5  1.26 

9 

2  0.22 

9 

i    1^1 

10 

£    J.  .  o  1 

10 

2  0.41 

10 

3  0.29 

10 

1     1  .  Ol 

11 

3  1.56 

10 

1  0.55 

11 

3  0.51 

9 

1  0.25  I 

11 

4  0.43 

11 

2  2.07 

12 

4  3.04 

11 

2  1.02 

12 

4  1.10 

10 

2  0.29 

12 

5   1.09 

12 

3  2.51 

12 

3  1.15 

13 

5  1.58 

11 

3  0.36 

13 

4  5.40 

13 

1   1.16 

13 

4  1.47 

12 

4  0.51 

13 

1  0.18 

14 

2  1.25 

14 

5  3.34 

14 

1  0.34 

13 

5  1.22 

14 

2  0.22 

14 

1   1  .46 

15 

3  1.48 

i 

15 

2  0.38 

15 

3  0.29 

15 

16 

4  2.47 

15 

1  0.52 

16 

3  0.48 

14 

1  0.23 

16 

4  0.42 

16 

2  2.01 

17 

5  8.39 

16 

2  0.58 

17 

4  1.06 

15 

2  0.27 

17 

5   1.08 

17 

3  2.40 

17 

3  1.10 

18 

5  1.49 

16 

3  0.34 

18 

4  5.00 

18 

1   1.12 

18 

4  1.39 

17 

4  0.49 

18 

1  0.18 

19 

2  1.20 

19 

5  3.08 

19 

1  0.32 

18 

5  1.18 

19 

2  0.22 

19 

20 
21 
22 
23 

1   1.42 
2  1.56 
3  2.31 
4  4.35 

20 

21 
22 

2;: 
24 

3  1.40 
,  4  2.31 
5  6.49 

1   1.07 
2  1.15 

20 
21 
22 
23 
24 

1  0.48 
2  0.54 
3  1.05 
4  1.32 
5  2.51 

!  20 
21 
22 
23 

24 

2  0.36 
3  0.45  ! 
4  1.02 
5  1.42 

1  0.30 

19 
20 
21 
22 

23 

1  0.22 
2  0.26 
3  0.33 
4  0.47 
5  1.15 

20 
21 
22 

23 
24 

3  0.29 
4  0.42 
5   l.OS 

1  0.18 
2  0.22 

24 

1  1.37 

2--> 

3  1.33 

25 

2  0.34 

24 

1  0.21 

25 

3  0.29 

25 

o  i   f»n 

26 

4  2.18 

25 

1  0.45 

26 

3  0.42 

25 

2  0.25 

26 

4  0  42 

26 

—    1  .  OU 

27 

5  5.29 

2(5 

2  0.50 

27 

4  0.58 

26 

3  0.32 

27 

5   1.08 

27 

3  2.22 

27 

3  1.01 

28 

5  1.36 

27 

4  0.46 

28 

4  4.07 

28 

28 

4  1.25 

28 

5  1.13 

28 

1  0.18 

29 

2!) 

5  2.34 

29 

1  0.28 

9Q 

2  0.22 

29 

1   1.32 

30 

2  0.32 

29 

1  0.20 

J*9J 

3  0.29 

on 

2  1.44 

30 

1  0.42 

2  0.24 

30 

4  0  43 

oU 

3  2.13 

31 

2  0.47 

30 

3  0.31 

31 

4  3.41 

4  0.44 

31 

5  1.11 

*  These  corrections  are  strictly  correct  for  the  middle  day  only  of  the  five-day  period,  for  the  hours  as  shown. 
In  the  case  of  extreme  days  of  the  period,  an  interpolation  may  be  made. 


12C 


THE    A.    LTETZ    COMPANY. 


REFRACTION    CORRECTION. 

LATITUDE  40°. 


July 

Refraction 
Correction 
Lat.  40  deg. 

Aug. 

Refraction 
Correction 
Lat.  40  deg. 

Sept. 

Refraction 
Correction 
Lat.  40  deg. 

Oct. 

Refraction 
Correction 
Lat.  40  deg. 

Nov. 

Refraction 
Correction 
Lat.  40  deg. 

Dec. 

Refrac- 
tion Cor. 
rection 
Lat. 
40  deg. 

h.    '     " 

h.    '     " 

h. 

h.      '     " 

A.'T 

1 

5    1.09 

1 

1 

1  0.39 

1 

1     0.59 

1 

2     1.37 

1 

1  1.54 

2 

2 

2  0.44 

2 

2     1.06 

2 

3     2.04 

2 

2  2.11 

h.   '     " 

3 

3  0.54 

3 

3     1.21 

3 

4     3.21 

q 

3  2.59 

3 

1  0.19 

2 

1  0.26 

4 

4  1.14 

4 

4     1.56 

4 

5  13.57 

o 

4  6.01 

4 

2  0.23 

3 

2  0.30 

5 

5  2.08 

5 

5     4.04 

4 

5 

5 

3  0.30 

4 

3  0.37 

5 

1     1.32 

6 

4  0.43 

5 

4  0.53 

6 

1  0.42 

6 

1     1.03 

6 

2     1.44 

5 

1   1.58 

7 

5  1.10 

6 

5  1.26 

7 

2  0.47 

7 

2     1  .  10 

7 

3    2.13 

6 

2  2.16 

8 

3  0.57 

8 

3     1.27; 

8 

4     3.41 

7 

3  3.04 

8 

1  0.20 

7 

1  0.28 

9 

4  1.19 

9 

4     2.061 

9 

5 

8 

4  6.23 

9 

2  0.24 

8 

2  0.32 

10 

5  2.18 

10 

5     4.39 

9 

5 

10 

3  0.31 

9 

3  0.39 

10 

1     1.37 

11 

4  0.44 

10 

4  0.55 

11 

1  0  45 

11 

1     1.07 

11 

2     1.50 

10 

1  2.00 

12 

5  1.11 

11 

5  1.30 

12 

2  0.50 

12 

2    .1.15 

12 

3     2.22 

11 

2  2.19 

13 

3  1.01 

13 

3     1.33 

13 

4     4.07 

12 

3  3.09 

13 

1  0.21 

12 

1  0.30 

14 

4  1.25 

14 

4     2.18 

14 

5 

13 

4  6.38 

14 

2  0.25 

13 

2  0.34 

15 

5  2.34 

15 

5    5.39 

14 

5 

15 

3  0.32 

14 

3  0.42 

15 

1     1.42 

16 

4  0.46 

15 

4  0.58 

16 

1  0.48 

16 

1     1.12 

16 

2     1.56 

15 

1  2.01 

17 

5  1.13 

16 

5  1.36 

17 

2  0.54 

17 

2     1.20 

17 

3     2.31 

16 

2  2.20/ 

18 

3  1.05 

18 

3     1.40 

18 

4     4  35 

17 

3  3.11 

18 

1  0.22 

17 

1  0.32 

19 

4  1.32 

19 

4     2.31 

19 

5 

18 

4  6.47 

19 

2  0.26 

18 

2  0.36 

20 

5  2.51 

20 

5     6.29; 

19 

5 

20 

3  0.33 

19 

3  0.45 

20 

1     1.46 

21 

4  0.47 

20 

4  1.02 

21 

1  0.52 

21 

1     1.16 

21 

2     2.01 

20 

1  2.01 

22 

5  1.15 

21 

5  1.42 

22 

2  0.58 

22 

2     1.25 

22 

3    2.40 

21 

2  2.20 

23 

3  1.10 

23 

3     1.48 

23 

4    4.59 

22 

3  3.11 

23 

1  0.23 

22 

1  0.34 

24 

4  1.39 

24 

4    2  47 

24 

5 

23 

4  6.49 

24 

2  0  27 

23 

2  0.38 

25 

5  3.08 

25 

5     8.39: 

•24 

5 

'25 

3  0.34 

24 

3  0.48 

25 

1     1.50 

26 

4  0.49 

25 

4  1.06 

26 

1  0.55 

26 

1     1.2li 

26 

2     2.06 

25 

I  2.00 

27 

5  1.18 

26 

5  1.49 

27 

2  1.02 

27 

2     1.31 

27 

3    2.49 

26 

2  2  19 

28 

3  1.15 

28 

3     1.56 

28 

4    5.33 

27 

3  3.09 

28 

1  0.25 

27 

1  0.36 

29 

4  1  47 

29 

4     3.04 

29 

5 

28 

4  6.4a 

no 

2  0.29 

28 

2  0.41 

30 

5  3.34 

30 

5  11.01 

29 

5 

JOf 

3  0.36 

29 

3  0.51 

30 

30 

4  0.51 

30 

4  1.10 

1     1  26 

30 

31 

5  1.22 

31 

5  1.58 

31 

! 

31 

No    7 

THE   CYCLOTOMIC   TRANSIT 

BY 

OTTO   VON  GKLDERN 
THE  PRINCIPLE  OF  THE  INSTRUMENT. 

The  evolution  of  this  instrument  is  due  to  a  constant  tendency  to  create  a  transit  with 
one  spindle,  i.  <?.,  having  but  one  central  cone  turning  within  the  leveling  head,  that  shall, 
at  the  same  time,  sacrifice  none  of  the  advantages  that  the  so-called  compound  center  pos- 
sesses. 

It  goes  without  saying  that  the  principal  advantage  of  the  double  spindle  lies  in  the 
fact  that,  no  matter  in  what  direction  the  telescope  may  be  pointed,  the  operator  is  enabled 
to  make  any  azimuth  of  his  graduated  plate  agree  therewith.  How  this  may  be  done  with- 
out giving  the  lower  plate  an  independent  motion  around  the  vertical  axis  of  the  instru- 
ment, is  the  problem  to  be  solved. 

The  lower  plate  is  the  important  member  that  carries  the  graduated  azimuth  circle, 
and  if  it  be  made  a  part  of  the  rigid  sub-structure — of  the  leveling-head  and  base-plate — 
the  control  of  it  in  reference  to  known  azimuths  is  apparently  lost.  If  we  were  enabled, 
however,  to  shift  the  figure-series— the  nomenclature  of  the  circle — at  will,  so  as  to  make 
any  one  of  the  graduation  lines  the  zero,  the  advantage  lost  by  having  a  rigid  lower  plate 
would  be  regained. 

The  novelty  of  the  new  transit  lies  in  a  floating  exterior  ring,  placed  around  the  periph- 
ery of  the  lower  plate,  upon  which  the  figures  from  o  to  360  are  engraved.  These  fig- 
ures are  then  no  longer  a  fixed  part  of  the  circle,  but  possess  that  independent  rotation 
which  the  lower  plate  had  in  the  case  of  the  double  spindle.  Instead  of  turning  the  whole 
plate  around  its  vertical  axis,  we  turn  a  narrow  metal  band  around  the  stationary  plate, 
which  is  the  same  thing. 

As  this  band  appears  to  be  sliced  from  the  plate,  the  name  Cyclotome  has  been  applied 
to  it,  from  xvxA.o's,  ring  or  circle,  and  rejuisetr,  to  cut,  that  is,  a  ring  cut  or  severed  as 
from  a  disk. 

Since  the  object  of  the  ring  is  merely  to  designate  the  graduated  lines  upon  the  plate 
by  corresponding  figures,  absolute  concentricity  of  the  cyclotome  is  not  a  matter  of  import- 
ance. 

THE   CONSTRUCTION. 

Attention  is  drawn  to  the  illustrations  herewith,  figure  I  showing  a  vertical  section 
through  the  plates,  and  figures  2  and  3  a  top  and  bottom  view  respectively  of  the  upper 
plate.  In  the  vertical  section  the  arrangement  of  the  principal  parts  may  be  readily  un- 
derstood. 

The  lower  plate  and  the  leveling-head  become  one  member,  which  is  mounted  upon 
the  base-plate  in  the  ordinary  manner.  The  cyclotome  C  is  fitted  exteriorly  around  the 
plate,  its  top  resting  upon  the  graduation,  of  which  it  is  a  part. 

The  upper  plate  revolves  upon  the  lower  by  means  of  its  long  and  stout  spindle,  within 
the  socket  of  the  leveling-head.  It  carries  the  vernier  V,  visible  through  an  opening  in  the 
plate,  which  also  exposes  a  part  of  the  graduated  lower  plate  and  a  part  of  the  cyclotome. 


through  JPl&fef 

L/r?e     X   -  Center-  -  X, 

c?/"  7e/e<scope 


A.  LIETZ  (JO 


All  rinJtts  reserved 


X. 


Fig.  2. 


Top  Y/ew 


Fig.  3. 
V/ew  of*  (/p/oer 


A.  LLkTZ  CO. 


124  MODERN   SURVEYING  INSTRUMENTS. 

The  horizontal  motion  of  the  instrument  is  arrested  by  the  clamp  and  collar,  and  the  posi- 
tion adjusted  by  a  tangent  screw,  as  common  to  all  transits. 

Compass  box  and  telescope  are  mounted  on  the  top  of  the  plate,  as  usual. 

The  flange  forming  the  top  of  th'e  lower  plate  is  graduated  into  72°  even  spaces  of 
half-degree  divisions.  The  vernier  moves  along  the  inner  rim  of  this  graduation,  and  is 
held  whenever  the  line  of  collimation  (the  telescope)  has  the  desired  direction.  In  order 
to  effect  a  coincidence  between  the  vernier's  zero  and  the  nearest  half-degree  division  , 
the  entire  vernier  may  be  shifted  independently  to  the  right  or  left  by  means  of  the  screw 
At  shown  in  the  illustrations,  and  in  the  manner  presently  to  be  explained. 

And  having  thusly  determined  upon  and  indicated  one  of  the  720  lines  to  be  the  initial 
or  starter,  it  would  be  necessary  only  to  bring  the  zero  of  thecyclotome— or  any  other  read- 
ing for  that  matter — to  match  this  line. 

In  the  simpler  form  of  the  new  transit,  the  exterior  ring  or  cyclotome  is  revoluble  by 
hand  around  the  periphery  of  the  plate,  and  the  required  azimuth  is  thus  readily  set  off.  In 
the  improved  form,  as  shown  by  the  illustrations,  the  ring  is  encased,  and  so  arranged  that 
the  upper  plate  in  its  rotation  may  or  may  not  carry  the  cyclotome  with  it.  It  is  picked  up 
and  revolved  together  with  the  telescope,  or  left  at  rest  upon  the  lower  plate  in  any  desired 
position.  It  is  wilhin  the  power  of  the  operator  to  manipulate  this  at  will,  and  there  are 
two  means  of  doing  so,  as  will  be  noted  further  on. 

As  it  is  generally  required  to  place  the  zero  upon  the  azimuth  from  which  observations 
are  started,  an  automatic  catch  L  (see  figure  3),  having  a  small  projecting  pin  »,  is  so  ar- 
ranged that  whenever  it  is  desired  to  make  the  cyclotome  travel  together  with  the  upper 
plate,  the  pin  n  must  be  made  to  drop  into  a  hole  provided  for  it  in  the  cyclotome  ;  the 
moment  this  takes  place,  the  two  (plate  and  cyclotome)  are  connected,  and — this  is  a  pecu- 
liar feature  of  the  device — in  such  a  position  that  the  zero  of  the  vernier  F,  and  the  zero  of 
the  cyclotome  C  are  brought  together,  separated,  of  course,  by  the  intervening  graduated 
flange  of  the  lower  plate.  If  the  vernier  be  now  revolved  with  the  upper  plate,  the  figure- 
system  will  travel  with  it,  their  respective  zeros  coinciding. 

The  bottom  of  the  upper  plate,  figure  3,  illustrates  the  mechanism  with  which  all  this 
is  accomplished.  £7is  a  guide,  fastened  to  the  plate,  for  the  arc  W>  carrying  the  vernier  V. 
A  strong  spring  S  presses  the  arc  against  the  slide  T,  the  position  of  the  whole  being  regu- 
lated by  the  exterior  screw  Ay  which  allows  the  adjustment  of  the  vernier  already  referred 
to.  The  catch  L  is  poised  in  T.  The  screw  B  raises  or  lowers  the  catch,  so  that  with  it 
we  may  throw  the  cyclotome  either  in  or  out.  A  small  spring  under  the  catch  L  admits  of 
this.  The  mechanism  is  so  simple  that  it  needs  no  further  description. 

With  this  device  there  is  no  difficulty  in  placing  the  zero  of  the  horizontal  circle  so  as 
to  correspond  with  any  pointing  of  the  telescope. 

USE    IN    THE    FIELD. 

The  field  manipulation  is  reduced  to  a  minimum. 

Having  set  the  instrument  over  a  point  (i)  in  the  usual  manner,  it  is  desired  to  direct 
the  telescope  to  another  point  (2),  and  to  make  the  zero  of  the  horizontal  graduation  corres- 
pond with  this  azimuth.  The  main  clamp  being  loose,  the  first  operation  is  to  turn  the 
screw  B  so  that  the  catch  L  is  depressed  ;  the  upper  plate  is  then  turned,  until  a  click  indi- 
cates that  the  little  pin  n  has  caught  the  cyclotome  and  is  carrying  it  along,  with  the  zero  in 
position,  as  explained.  The  operation  is  automatic  to  this  extent,  that  the  manipulator 
need  not  watch  his  plate  to  set  the  zeros.  He  will  now  direct  the  telescope  to  point  (2), 
clamp  the  plate,  and  bisect  the  object  with  the  tangent  screw.  His  attention  is  thereupon 
directed  to  the  vernier,  for  it  is  essential  that  its  zero  should  correspond  exactly  with  a  line 
of  the  fixed  graduation.  He  turns  the  screw  A  to  the  right,  or  left,  shifting  the  vernier 


THE    A.    LIETZ   COMPANY.  125 

sufficiently  to  accomplish  this.  The  cyclotome  travels  with  the  vernier,  so  that  he  does 
not  need  to  watch  it.  The  instrument  is  now  oriented,  the  vernier  indicating  the  starting 
azimuth,  "and  measurements  to  other  points  may  begin.  Before  commencing,  however,  the 
screw  B  is  turned  so  as  to  release  the  catch  and  allow  the  cyclotome  to  remain  in  position. 
The  instrument  is  now  undamped  and  ready  for  operation.  Any  subsequent  reading  will 
indicate  directly  in  degrees  and  minutes  the  deflection  from  the  starting  point.  The  whole 
operation  is  simple  and  rapid,  and  will  require  less  time  than  the  setting  of  the  compound- 
center  instrument. 

If  it  be  desired  to  set  any  other  azimuth  to  a  telescope  pointing,  recourse  is  had  to  the 
clamp  F  (see  top  view  of  plate,  figure  2),  by  which  the  cyclotome  may  be  connected  to  the 
upper  plate  at  any  point. 

The  operation  it  as  follows  : 

Set  up  instrument ;  drop  catch  L  by  a  turn  of  screw  B  ;  revolve  plate  on  center,  click 
indicates  that  L  has  caught  cyclotome  (7;  point  telescope,  clamp  plate  and  bisect  object  j 
shift  zeros  to  the  nearest  graduation  line  by  screw  A  ;  release  cyclotome  by  screw  B ;  un- 
Clamp  instrument  and  lay  off  the  reading  of  the  required  azimuth  to  the  nearest  thirty 
minutes  by  means  of  the  clamp  and  tangent  screws,  and  then  to  the  minute  with  precision 
by  means  of  the  screw  A  ;  now  turn  down  the  screw  F,  which  catches  the  cyclotome  ;  un- 
clamp  instrument,  revolve  on  center,  direct  telescope  to  original  object,  clamp  and  bisect. 
The  reading  of  the  vernier  will  now  indicate  the  azimuth  wanted.  Release  the  screw  F' 
and  the  cyclotome  will  remain  in  the  position  into  which  it  has  been  brought. 

The  reason  why  the  reading  is  laid  off  to  the  nearest  thirty-minute  mark  only,  and  then 
adjusted  to  precise  reading  by  shifting  the  vernier,  becomes  obvious,  if  we  remember  that  it 
is  always  necessary  to  match  the  graduation  lines  of  the  plate  with  those  of  the  cyclotome,. 
and  that  any  setting  disturbing  their  coincidence  (readings  from  ix  to  29'  and  31*  to  59')  wilt 
have  to  be  corrected  by  a  vernier  displacement. 

This  operation  is  rapid,  although  perhaps  a  trifle  slower  than  the  manipulation  with 
the  hand  cyclotome,  mentioned  above,  in  which  case  the  telescope  is  directed,  plate  clamped, 
object  bisected,  vernier  zero  brought  to  a  line,  cyclotome  turned  by  hand  to  read  within  the 
nearest  half  degree  of  the  line,  after  which  the  vernier  is  adjusted  to  the  exact  reading. 

The  principle  remains  the  same  in  either  method,  the  only  difference  being  that  in  the 
case  of  the  hand  cyclotome  one  is  able  to  set  it  irrespective  of  the  motions  of  the  uppe 
plate. 

After  these  explanations  it  becomes  very  obvious  that  there  are  no  advantages  that  the 
double  spindle  system  can  claim  over  the  cyclotomic  system  in  the  ready  manipulation  of 
the  horizontal  arc. 

ANGULAR    REPETITION. 

While  the  reiteration  of  an  angle,  resorted  to  in  geodetic  measurements,  to  obtain  the 
value  of  an  arc  with  its  probable  error  to  the  fraction  of  a  second,  is  not  possible  with  the 
cyclotomic  transit,  because  the  main  graduation  is  fixed  and  cannot  be  turned  in  reference 
to  the  direction  of  the  objects  observed  upon,  it  is  perfectly  feasible  to  take  the  same  angle 
on  different  parts  of  the  plate.  Since  there  are  two  verniers,  located  180  degrees  apart,  twa 
readings  may  also  be  had  of  each  measurement  and  the  mean  taken. 

Unless  a  double  spindle  transit  be  of  the  very  best  workmanship,  that  is,  a  first-class, 
and  therefore  a  high-priced  article,  all  the  reiteration  and  repetition  will  fail  to  reach  a 
better  result  than  that  attainable  with  a  well  built  cyclotomic  instrument,  which  is  made  to* 
read  to  half  minutes  directly,  or  to  twenty  seconds  in  the  larger  sizes  ;  and  anything  within 
the  limits  of  this  accuracy  is  guaranteed  by  the  maker.  As  the  reiteration  of  an  angle  is. 
uncalled  for  in  any  but  the  most  refined  measurements,  the  cyclotomic  transit  does  not  lack 
completeness  for  the  want  of  this  particular  feature. 


126  MODERN   SURVEYING   INSTRUMENTS. 

ADVANTAGES   OF   THE   CYCLOTOMIC   TRANSIT. 

The  main  feature  is  its  single  spindle.  Its  adoption  obviates  the  necessity  of  the  lower 
clamp  and  tangent  screws,  and  simplifies  this  part  of  the  transit  very  much.  It  affords  an 
opportunity  to  bring  the  plates  closer  to  the  leveling-head,  thereby  lowering  the  center  of 
gravity  of  the  instrument.  It  sits  directly  upon  the  rigid  substructure,  fitted  into  it  by  a 
thick  metal  axis  and  must  therefore  be  very  steady.  The  main  graduation,  the  most  vital 
part  of  the  transit,  is  fixed  for  all  time.  Once  properly  centered,  the  chances  for  eccentri- 
city are  reduced  to  a  minimum.  The  instrument  possesses  a  comparing  vernier,  opposite  the 
reading  vernier,  (see  figure  2)  which  shows  through  a  circular  opening  in  the  plate.  By 
means  of  the  two,  used  in  conjunction,  the  plate  eccentricity  may  be  accurately  determined- 

What  is  justly  claimed  for  this  instrument  as  more  advantageous  than  the  compound- 
center  transit  is  included  in  the  following  : 

Greater  simplicity  ;  reduction  of  parts  and  reduction  of  weight,  with  greater  steadiness 
for  instruments  of  the  same  size  ;  greater  solidity  of  the  axis,  and  therefore  greater  rigidity, 
and  the  least  liability  to  serious  injury  through  accident ;  simple  mechanism  enabling  a 
more  rapid  setting  of  the  plates  to  the  zero  azimuth  ;  avoiding  the  manufacture  of  an  extra 
cone  and  socket,  that  is,  reduction  of  prominent  and  costly  parts  to  be  made  by  the  artisan, 
and  a  reduction,  therefore,  of  the  price  of  the  article. 

In  its  optical  appointments  and  constructive  details,  the  instrument  is  up  to  the  stand- 
ard of  a  first-class  modern  transit  and  surveying  instrument  ;  it  is  a  tachymeter,  and  fitted 
for  any  possible  expediency  of  modern  engineering. 

It  has  not  been  the  object  to  replace  the  compound-center  instrument  with  a  cheap 
and  inferior  substitute,  but  rather  to  simplify  the  required  parts  and  to  improve,  if  possi- 
ble, the  stability  and  concentricity,  without  losing  those  features  that  have  thus  far  made 
the  double-center  instrument  the  preferred  one  for  meeting  the  manifold  demands  made  by 
the  profession  upon  a  universal  measuring  tool. 

THE  MANUFACTURE. 

The  instrument  in  its  present  shape  was  designed  in  detail  by  Mr.  Adolph  Lietz,  the 
original  suggestion  having  be'en  made  to  him  by  Mr.  Luther  Wagoner,  civil  engineer,  of 
San  Francisco,  who  had  conceived  the  application  of  the  floating  ring  or  cyclotome. 

All  rights  have  been  legally  secured  by  the  designer,  who  is  also  the  manufacturer. 

The  instrument  is  made  in  San  Francisco,  in  different  styles  and  sizes.  In  their  main 
and  essential  parts  all  styles  are  alike,  but  they  may  vary  a  little  in  the  arrangement  of 
minor  detail.  In  appearance  the  instrument  does  not  differ  from  any  standard  typt,  except 
that  the  bulky  apparatus  of  clamp,  collar,  tongue,  spring -case  and  tangent  screw  below  the 
plates  is  missing,  and  that  the  plates  sit  a  little  closer  to  the  base. 

The  cyclotomic  transit  is  particularly  adapted  to  aluminium  construction,  by  placing  a 
light  superstructure  upon  a  firm  and  solid  base.  This  will  insure  very  great  steadiness  even 
in  a  strong  wind. 

REMARKS. 

It  is  very  probable  that  the  instrument  will  work  itself  into  the  favor  of  the  profession, 
for  while  it  has  been  much  simplified,  nothing  has  been  sacrificed,  and  the  item  of  cost  has 
been  reduced. 

The  principle  here  made  use  of  may  be  extended  with. ad  vantage  to  many  forms  of  arc- 
measuring  apparatus,  and  will  undoubtedly  find  a  much  wider  application  in  time.  Al- 
though extremely  simple  and  readily  understood  by  anyone,  it  will  require  a  little  field 
practice  to  make  the  engineer  an  expert  in  the  use  of  the  cyclotome,  which,  like  the  slide- 
rule,  will  be  appreciated  all  the  more  the  longer  it  is  used  and  its  advantages  become 
apparent. 


REVISED    EDITION    OF 


ILLUSTRATED  CATALOGUE  AND  PRICE  LIST 

OF 

MODERN 

ENGINEER'S  AND  SURVEYOR'S  INSTRUMENTS, 

GUARANTEED  IN  EVERY  DETAIL. 

MA  OK    n\ 

THE    A.    LIETZ   COMPANY, 

Manufacturers    of    Scientific    Instruments 
No.  422  SACRAMENTO  STREET, 


SAN  FRANCISCO, 
CALIFORNIA. 


INTRODUCTION  TO  PART  IV. 


P  MHE  following  illustrations  show  the  principal  articles  man- 

ufactured  by  this  Company,  being  in  the  case  of  this  cata- 
logue almost  exclusively  confined  to  instruments  required  by 
the  civil,  mining,  irrigation,  hydraulic  and  military  engineer, 
for  making  accurate  measurements  and  surveys  for  any  purpose 
whatever. 

Of  the  surveying  instruments  each  illustration,  or  plate,  is 
coinj  iete  within  itself.  Every  part  is  carefully  noted  upon  the 
back,  together  with  the  price,  and  a  general  description  in  a 
condensed  form.  The  additional  accessories  that  may  be  had 
in  each  instance,  are  also  enumerated  and  their  prices  given. 
It  is  well,  however,  that  the  engineer  who  is  looking  for  an 
article,  should  consult  the  preceding  Part  II  of  this  Manual, 
wherein  every  detail  is  carefully  described  and  extensively  dis- 
cussed. If  pains  are  taken  to  look  this  over,  the  reader  will 
obtain  all  the  information  that  could  possibly  be  given  him  in 
the  shop. 

Every  article  has  been  numbered,  and  by  these  numbers 
our  customers  may  order,  without  going  into  a  minute  descrip- 
tion of  the  articles  wanted.  For  example- 

"  Send  me  transit  No.  4,  (1896)  with  the  following  extras ' 

is  all  that  is  required  to  designate  to  us  exactly  what  is  desired  by  our 
patron. 

In  ordering  please  mention  the  issue  of  the  catalogue,  as  the  num- 
bers of  preceding  issues  necessarily  conflict. 

With  the  detailed  information  on  its  reverse  side,  every 
plate  becomes  a  complete  price  list  of  the  particular  instrument 
illustrated.  Every  effort  has  been  made  to  make  this  part  of 
the  book  as  intelligible  as  possible,  without  the  necessity  of 
searching  over  numerous  pages  to  gather  information. 


THE    A.     LIETZ    COMPANY.  129 

Although  we  shall  make  any  instrument  of  precision  called 
for,  we  desire  to  state  clearly  that  we  have  made  a  particular 
specialty  of  engineer's  and  surveyor's  instruments,  because 
there  is  for  them  alone  a  demand  at  the  present  time,  and  for 
this  reason  our  shop  facilities  have  been  especially  designed 
and  improved  for  the  manufacture  of  these  articles. 

If  instruments  for  a  more  scientific  purpose  are  wanted,  for 
astronomical  or  geodetic  work,  for  instance,  we  can  either  make 
them  on  a  special  order,  or  we  can  import  them  for  our  customer, 
having  made  arrangements  in  Europe,  which  enables  us  to  sell 
such  instruments  as  cheaply  as  any  one  in  the  United  States. 
For  institutions  of  learning  we  import  without  payment  of  duty. 

We  have  added  a  number  of  illustrations  of  imported  astro- 
nomical and  geodetic  instruments,  which  are  marked  with  a  f, 
to  distinguish  them  from  our  own  make.  We  shall  be  glad  to  furnish 
an  estimate  of  the  probable  cost  of  these  articles. 

In  all  our  manufacture  the  prices  have  been  marked  com- 
mensurate with  the  quality  of  the  work,  and  no  deductions  can 
be  made  from  our  price  list,  which  agrees  in  all  its  quotations 
with  those  of  our  best  Eastern  firms. 

We  furnish  a  first-class  article  at  a  fair  price,  and  all  goods 
stand  upon  their  individual  merit.  It  is  our  object  to  introduce 
the  Lietz  instrument  to  the  profession  generally,  and  to  prove 
all  the  claims  that  we  are  making  for  it,  and  with  our  earnest 
effort  and  encouragement  we  feel  confident  of  future  success. 

Our  Cyclotomic  Transit  which  we  brought  into  the  market 
several  years  ago,  has  been  successfully  introduced.  The  especial 
and  careful  attention  of  our  practitioners  is  hereby  called  to  this 
simple  and  valuable  instrument. 

THE    A.    LIETZ   COMPANY. 


Engineer's  and  Surveyor's  Transits, 

Nos.   1   to  4. 

These  are  elegant  instruments,  absolutely  accurate  in  all 
working  parts,  designed  for  land  surveying  and  engineering 
work  of  a  high  character. 

The  general  dimensions  are  given  011  the  back  of  each  il- 
lustration, as  well  as  the  price,  and  the  extras  that  may  be  had 
upon  application.  By  carefully  inspecting  the  plates,  the  price 
list  and  the  enumerated  extras,  the  purchaser  is  enabled  to 
choose  the  article  and  any  desired  accessory,  and  make  an  esti- 
mate of  its  cost. 

We  make  each  style  in  hard  aluminium,  which  increases 
the  price  15%. 

The  horizontal  circle  is  graduated  to  read  to  either  60,  30  or 
20  seconds,  two  double  verniers  being  provided,  placed  so  as  to 
afford  a  reading  without  stepping  aside.  The  vertical  arc  or 
circle  is  graduated  to  read  to  60  or  30  seconds.  Every  instru- 
ment has  long  compound  centers,  shifting  plates  on  tripod 
head,  with  new  improved  coupling.  The  telescope  possesses 
definition,  light  and  power  in  a  high  degree.  -It  has  Jena  glass 
lenses,  achromatic  objective  and  eye-piece.  Erect  vision. 
The  telescope  is  reversible  and  evenly  balanced,  provided  with 
slide  protector,  and  screw  motion  for  focusing  cross-hairs.  The 
standards  are  cloth-finished.  The  case  has  leathern  straps,  rub- 
ber cushions,  and  contains  all  the  usual  accessories.  For  a 
minute  description  of  every  detail,  see  Part  II  of  the  Manual. 


FHE  A.  LIETZ  Cos 
MAKERS, 

SAN  FRANCISCO, 


No.  1. 
PLAIN  TRANSIT. 

Price,  $185.00. 

For  details  and  extras  see  the  following  page. 

131 


No.  i. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  the  edge  of  graduation) 6j^  inches  diam. 

Compass  Needle 4%       "       long 

Object  Glass I  /i       "     diam. 

Telescope 1 1  ".      long 

Magnifying  power 24 

Weight  of  instrument  , 15      Ibs. 

tripod sy2  " 

box 8       " 

Weight  of  this  instrument  if  made  of  hard  aluminium 7J4  " 

The  price  of  this  instrument  as  shown  is $l$$  °° 

And  if  made  of  hard  aluminium,  15  per  cent  are  added. 

The  Extras,  for  which  additional  charge  is    made,  are   as  follows: 

Solid  Silver  Graduations  : 

On  horizontal  circle $1000 

Verniers,  reading  to  30" 10  oo 

"  "  20" 2000 

Stadia  hairs,  fixed 3  oo 

"         "      adjustable 10  oo 

Variation  plate 10  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope    20  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four 10  oo 

Three  leveling-screw  shifting  center ^ 5  oo 

Extra  extension  tripod 1 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

NOTE. — On  all  Lietz  Transits  the  variation  of  the  needle  may  be  laid 
off  to  the  minute,  see  page  24. 


132 


LIETZ  COM  PA; 
MAKEKS, 

SAN  FRANCISCO,  CAJ 


No.  2. 
TRANSIT,  WITH  LEVEL  TO  TELESCOPE. 

Price,  $215.00. 

•For  details  and  extras  see  the  following  page. 

133 


No.  2. 

Dimensions  and   "Weight. 

Horizontal  Circle  (measured  to  the  edge  of  graduation) 6^  inches  diam. 

Compass  Needle 4^2        "       long 

Object  Glass iK      "     diam. 

Telescope 1 1          "        long 

Magnifying  power 24 

Weight  of  instrument 15      Ibs. 

tripod 8/2     " 

box 8 

Weight  of  this  instrument  if  made  of  hard  aluminium 7%     " 

Tine  price  of  this  instrument  as  shown  is $2 1 5  oo 

And  if  made  of  hard  aluminium,  15  per  cent  added. 

The  Extras,  for  which  additional  charge  is  made,  are   as  follows  : 

Solid  Silver  Graduations  : 

On  horizontal  circle $10  oo 

Verniers,  reading  to  30" IO  oo 

"            "            20" 20  oo 

Gradienter  Attachment .  .  5  oo 

Stadia  hairs,  fixed 3  OO 

"           "      adjustable 10  oo 

Variation  plate 10  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  co 

Reversion  level  for  telescope  (see  slip  I34A) 10  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four 10  oo 

Three  leveling-screw  shifting  center 5  oo 

Extra  extension  tripod 1 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 


134 


The 


lieVel. 


The  REVERSION  LEVEL  is  ground 
on  both  sides,  and  the  case  open  on  top 
and  bottom,  so  that  the  bubble  is 
always  visible  when  the  telescope  is 
revolved  in  transit.  Absolute  levels  may 
be  obtained,  and  errors  in  adjustment 
may  be  corrected  in  reversion,  by  a 
method  of  vertical  double  centering. 


l:M  A 


No.  3. 
COMPLETE  ENGINEERS'  TRANSIT, 

WITH  VERTICAL  ARC. 
Price,  $330.00. 

J3^-For  details  and  extras  see  the  following  page. 

The  5-inch  vertical  arc  is  provided  with  a  double  vernier,  reading  to  minutes. 

135 


DIE 

OF  THE 
UNIVFDQITV 


No.  3. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  edge  of  graduation) 6  finches  diam. 

Vertical  Arc  (measured  to  edge  of  graduation) 5  " 

Compass  Needle 4%  "       long- 
Object  Glass i  y$  "      diam. 

Telescope 11  "       long. 

Magnifying  power    , 24 

Weight  of  instrument <,.,.., 15  Ibs. 

tr.pod Sy2  " 

"  box 8 

Weight  of  this  instrument  if  made  of  hard  aluminium    . . .  7^  " 

The  price  of  this  instrument  as  shown  is $230  oo 

And  if  made  of  hard  aluminium,  15  per  cent  added, 

The  Extras,  for  which  additional  charge  is  made,  are  as  follows : 

Solid  Silver  Graduations  : 

On  horizontal  circle $10  oo 

On  vertical  arc 5  oo 

Verniers,  reading  to  30"  on  horizontal  circle 10  oo 

"  "  20"  "  " 2000 

Gradienter  Attachment 5  oo 

Stadia  hairs,  fixed 3  oo 

".        "      adjustable 10  oo 

Variation  plate 10  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Reversion  level  to  telescope  (see  slip  I34A) 10  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four   ....  10  oo 

Three  leveling-screw  shifting  center 5  oo 

Prism,  attachable  to  eye  piece 8  oo 

Extra  extension  tripod 15  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

Saegmiiller  Solar  Attachment  of  aluminium 50  oo 

136 


THE  A.  LIETZ  COMPANY 

MAKERS, 
SAN  FRANCISCO,  CJ|L. 


No.  4. 
COMPLETE  ENGINEERS'  TRANSIT, 

WITH  FULL  VERTICAL  CIRCLE. 
Price,  $235.00. 

ff^For  details  and  extras  see  the  following  page. 

The  5-inch  vertical  circle  is  provided  with  a  double  vernier,  reading  to  minutes. 

137 


No.  4. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  edge  of  graduation) 6%  inches  diam. 

Vertical  Circle  (measured  to  edge  of  graduation) 5           "  " 

Compass  Needle 4^       ' '  long. 

Object  Glass i^       "  diam. 

Telescope 1 1           "  long. 

Magnifying  power 24 

Weight  of  instrument 15        Ibs. 

tripod 8^       " 

"  box 8 

Weight  of  this  instrument  if  made  of  hard  aluminium. .   "j)4       " 

The  price  of  this  instrument  as  shown  is $235  oo 

And  if  made  of  hard  aluminium,  15  per  cent  added. 

The  Extras,  for  which  additional  charge  is  made,  are  as  follows : 

Solid  Silver  Graduations  : 

On  horizontal  circle $10  oo 

On  vertical  circle 5  co 

Verniers,  reading  to  30"  on  horizontal  circle 10  oo 

"                "                 20"                   "                 "         20  00 

Gradienter  Attachment 5  oo 

Stadia  hairs,  fixed 3  oo 

"   .     "    adjustable 10  oo 

Variation  plate 10  oo 

Arrangement  for  offsetting  right  angles ....    5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Reversion  level  to  telescope  (see  slip  I34A) 10  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four 10  oo 

Three  leveling-screw  shifting  center , 5  oo 

Prism,  attachable  to  eye-piece 8  oo 

Extra  extension  tripod 1 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

Saegm tiller  Solar  Attachment  of  aluminium 50  oo 

138 


No.  5. 
COMPLETE  TRANSIT-THEODOLITE. 

FOB  HIGHEST  GRADE  ENGINEERING  WORK. 
For  particulars  and  price,  see  the  following  page. 
139 


Ho.  5. 
TRANSIT-THEODOLITE. 

This  is  an  instrument  of  very  superior  construction. 

The  standards  upon  which  the  telescope  rests  are  cast  in  one  U-shaped  piece, 
thus  affording  more  strength  than  the  ordinary  form. 

The  telescope  is  reversible  in  position,  as  well  as  exchangeable  in  its  bearings, 
which  are  provided  with  dust-caps  and  screws,  to  give  them  the  proper  friction. 
The  telescope  is  either  erect  or  inverting.  For  reasons  already  set  forth,  the  in- 
verting form  should  be  given  the  preference.  The  telescope  possesses  the  finest 
lenses  and  optical  accessories.  It  has  a  slide  protector  and  is  provided  with  a  sun- 
shade. The  cross  hairs  are  focused  by  a  screw  motion  of  the  eye-piece. 

All  the  graduations  are  on  solid  silver.  The  horizontal  circle  reads  to  either 
30,  20  or  10  seconds,  by  two  opposite  verniers,  near  the  line  of  collimation,  which 
are  supplied  with  two  attached  reading  glasses,  if  desired.  The  vertical  arc  or  cir- 
cle is  graduated  to  read  to  30  seconds. 

The  instrument  is  furnished  with  either  three  or  four  leveling  screws,  that  op- 
erate through  a  slotted  star,  as  already  described  in  the  case  of  the  other  instru- 
ments. 

A  shifting  center  is  provided,  with  extra  cover  plate  to  protect  it  from  dust. 

The  U-shaped  casting,  constituting  the  support  for  the  telescope,  may  be 
either  in  cloth-finish,  or  in  bright  lacquer,  like  the  rest  of  the  instrument.  The 
metal  finish  may  be  had  of  any  desired  color. 

The  new  Lietz  Tripod  Coupling  is  furnished  without  extra  charge. 

The  case  contains  all  the  usual  accessories,  such  as  plumb  bob.  screw  driver, 
adjusting  pins,  etc. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  edge  of  graduation) 6%  inches  diam. 

Vertical  Arc  or  Circle  (measured  to  edge  of  graduation) 5          "         *' 

Compass  Needle  (in  box  on  plate) 3/^  long. 

Telescope II  "         " 

Object  Glass \l/$      "      diam. 

Magnifying  power , 24 

Weight  of  instrument 16        Ibs. 

"  tripod 8)4      " 

"  box 8          " 

If  made  of  aluminium,  the  weight  of  the  instrument  is  reduced  50%. 
The  price  of  the  plain  transit -theodolite  (without  a  level,  clamp  and  arc  to  tele- 
scope) is  $240.00,  and  if  made  of  hard  aluminium  15%  are  added. 

The  Extras,  which  make  the  instrument  more  or  less  complete, 
are  as  follows : 

Verniers  reading  to  20"  on  a  6^  i°cn  horizontal  circle $10  oo 

"             "         "  10"      "    7       "              "           "       35oo 

A  5-inch  vertical  arc,  reading  to  minutes 20  oo 

A  5-inch  full  vertical  circle,  reading  to  minutes 25  oo 

"         **         "         "        with  opposite  double  verniers,  reading  to  min- 
utes   N. , , .  50  oo 

Two  vernier  microscopes 1500 

Long  ground  level  to  telescope,  with  compound  clamp  and  tangent  screw, 

telescope  reversible,  and  supplied  with  gradienter  attachment 40  oo 

Reversion  level  to  telescope  (see  slip  1 34  A) 10  oo 

Striding  Level 20  oo 

Stadia  Hairs,  fixed 3  oo 

"           "       adjustable 10  oo 

Box  Needle,  on  plate 20  oo 

Constiucted  with  three  leveling  screws  on  base  plate,  instead  of  four 10  oo 

Three  leveling  screw  shifting  center 5  °° 

Prism  attachable  to  eye-piece 8  oo 

Protection  bag » I  oo 

Bottle  of  fine  watch  oil 25 

Saegmuller  solar  attachment  of  aluminium 5°  °° 

140 


THE  A.  LIETZ  Co  IPAXY, 
MAKERS, 

SAN  FRANCISCO   OAL. 


No.  9. 
COMPLETE  MOUNTAIN  AND  MINING  TRANSIT. 

Nos.  6  to  9. 

No.  6  is  the  Plain  Mountain  and  Mining  Transit. 
No.  7  the  same  as  No.  6,  with  telescope  level. 
No.  8  the  same  as  No.  7,  with  a  vertical  arc 

•For  details,  prices  and  extras,  see  the  following  page. 
141 


MOUNTAIN  AND  MINING  TRANSIT. 

No.  6. 
THE  PLAIN  TRANSIT. 

This  is  a  beautiful  instrument,  made  to  correspond  in  every  way  with  No.  i, 
except  in  size  and  weight.  It  is  a  superior  and  reliable  article  for  general  land. 
surveying,  and  particularly  for  mining  purposes. 

Dimensions,  Nos.  6  to  9. 

Horizontal  Circle  (measured  to  edge  of  graduation). ...    5  inches  diam 

Vertical  Arc  or  Circle  (measured  to  edge  of  graduation) 4        "         <; 

Compass  Needle 4%    ' '      long. 

Object  Glass I         "     diam. 

Telescope .' 8        ' '      long. 

Magnifying  power. .    18 

Weight  of  instrument • 8%  Ibs. 

"  tripod 6        " 

box 6 

Weight  of  this  instrument,  if  made  of  hard  aluminium 4%  " 

The  price  of  the  plain  transit,  No.  6   is $180  oo 

With  level  to  telescope  and  tangential  movement,  No.  7 210  oo 

With  Vertical  arc  in  addition,  No.  8 225  oo 

With  full  vertical  circle,  No.  9 230  oo 

And  if  made  of  hard  aluminium,  15%  are  added. 

The  Extras,  for  which  additional  charge  is  made,   are  as  follows  : 

Solid  Silver  Graduations  : 

On  horizontal  circle $10  oo 

On  vertical  arc  or  circle 5  oo 

Gradienter  Attachment 5  oo 

Stadia  hairs,  fixed 3  oo 

"         "       adjustable 10  oo 

Variation  Plate 10  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Reversion  level  for  telescope  (see  slip  134  A) 10  oo 

Constructed  with  three  leveling  screws  on  base-plate,  instead  of  four 10  oo 

Three  leveling-screw  shifting  center 5  °° 

Prism  attachable  to  eye-piece 8  oo 

Half-length  tripod 13  oo 

Extra  extension  tripod 1 5  co 

Extension  tripod  in  lieu  of  the  ordinary 5  °° 

Detachable  side  telescope 35  °° 

Lamp  for  mining  engineering,  of  brass,  with  ground  lens 7  °° 

Reflector,  for  illuminating  cross  hairs 4  oo 

Plummet  lamp 10  oo 

Large  plumb-bob,  weight  4  Ibs. ,  for  use  in  shafts 5  oo 

Protection  bag i  oo 

Bottle  of  fine  watch  oil 25 

Saegmuller  solar  attachment  of  aluminium 50  oo 

142 


No.    10.     Mining  Transit. 

The  same  dimensions  as  in  Nos.  1  to  4.  Graduations  on 
solid  silver;  verniers,  reading  to  minutes,  provided  with  glass 
shades;  5-inch  full  vertical  circle;  spirit  level,  clamp  and  tan- 
gent screw  to  telescope;  extension  tripod,  etc.  Price,  $258.00. 
If  made  of  hard  aluminium,  15%  added. 

No.   I  I .     Mining  Transit. 

The  same  dimensions  as  in  Nos.  6  to  9.  Graduations  on 
solid  silver;  verniers,  reading  to  minutes,  provided  with  glass 
shades;  4-inch  full  vertical  circle;  spirit  level,  clamp  and  tan- 
gent screw  to  telescope;  extension  tripod,  etc.  Price,  $253.00. 
If  made  of  hard  aluminum,  15%  added. 

It  must  be  apparent  that  there  cannot  be  any  great  differ- 
ence in  price  between  a  large  and  a  small-sized  instrument. 
The  workmanship  in  each  is  alike,  and,  if  anything,  more  com- 
plicated and  costly  in  the  smaller.  The  only  difference  is  i:i 
the  quantity  of  metal  used,  but  as  this  can  not  possible  amount 
to  much  in  price,  it  is  more  than  compensated  by  the  additional 
care  required  in  handling  the  smaller  parts.  This  explanation 
would  hardly  seem  necessary,  were  it  not  for  the  prevailing  im- 
pression that  all  merchantable  articles  of  the  same  kind  should 
be  rated  by  their  respective  sizes.  That  this  cannot  obtain  in 
the  case  of  instruments  must  stand  to  reason.  The  price  of  a 
transit  can  only  be  reduced  by  omitting  certain  features,  or  by 
changing  it  to  a  simpler  construction.  For  this  reason  we  have  in- 
vented and  are  now  building  an  instrument,  called  by  us  the  Cyclo- 
tomic  Transit,  to  which  your  attention  is  particularly  called.  See  pages 
121  and  153,  this  Manual. 


Simplified  Transit  Compasses 

These  instruments,  Nos.  12, 13  and  14,  are  high  grade  compasses 
possessing  transit  accessories;  but  as  there  is  no  graduated  horizontal 
plate,  they  are  only  fitted  for  needle  surveys. 

The  telescope,  mounted  upon  cloth-finished  standards,  has  the 
best  lenses,  accurately  centered  and  of  ample  power. 

The  needle  is  of  the  best  make,  and  may  be  read  with  the  same 
accuracy  as  that  of  any  other  transit. 

The  leveling  is  done  by  two  pairs  of  opposing  leveling  screws, 
mounted  horizontally  (see  the  appended  illustrations),  that  operate 
against  a  ball  in  a  socket,  admitting  of  a  very  accurate  adjustment  to 
the  proper  plane  indicated  by  two  sensitive  plate  bubbles.  While  one 
leveling  screw  is  loosened  or  drawn  out,  the  opposing  one  is  operated 
against  the  ball  until  the  inclination  of  the  vertical  axis  is  nil.  This  is 
done  with  both  sets  until  the  plate  bubbles  remain  centered  for  any 
position  in  azimuth.  The  ball  must  be  so  held  that  it  becomes  rigid 
and  the  axis  steady. 

These  compasses  are  made  of  standard  size  (refer  to  illustrations), 
and  in  three  varieties.  No.  12  is  the  plain  transit  compass.  No.  13 
has  in  addition  a  telescope  level  with  clamp  and  tangential  movement 
therefor.  No.  14  has  a  vertical  arc  and  is  completely  fitted  for  stadia 
work.  Surmounted  with  a  Saegmiiller  Solar  attachment,  this  compass 
becomes  the  Compound  Mining  and  Solar  Instrument  shown  in  No.  15, 
by  means  of  which  meridional  work  may  be  done  with  much  greater 
accuracy  than  with  the  old-fashioned  surveyor's  compass  having  metal 
sights,  or  the  cumbersome  solar  compass,  with  its  rough  motions  and 
its  crude  means  of  obtaining  approximately  the  direction  of  a  line. 
These  antiquated  relics,  although  costing  fully  as  much  as  our  transit 
compasses,  cannot  by  any  possibility  be  so  reliable. 

The  solar  attachment  possesses  the  additional  advantage  of  a  side 
telescope  for  certain  mining  work. 


144 


145 


SIMPLIFIED  TRANSIT  COMPASSES. 
No.  12. 

Possessing  a  long  center  ;  horizontal  leveling  screws,  and  ball  joint  movable 
in  socket.  No  horizontal  plate.  Compass  needle  and  graduated  compass  ring, 
with  variation  plate.  Sensitive  plate  levels.  Cloth  finished  standards,  carrying  a 
fine  achromatic  telescope.  The  telescope  is  reversible  and  accurately  balanced. 
It  affords  ample  definition,  power  and  light.  May  be  had  with  or  without  stadia 
hairs. 

The  instrument  is  packed  in  a  handsome  case  containing  a  plumb  bob,  ad- 
justing pins  and  all  the  usual  accessories. 

A  light  but  strong  tripod  is  furnished. 

Dimensions  and  Weight. 

Compass  Needle , 3^  inches  long. 

Telescope 8         "        long. 

Vertical  Arc 4         "       diam. 

Object  Glass I         " 

Magnifying  power 18 

Weight  of  instrument 7%  Ibs. 

"         tripod 6 

"         box 4%    " 

The  price  of  this  instrument  is $80.00 

Stadia  hairs,  $3.00  extra. 

No.  13. 

The  same  as  No  12,  with  a  level  to  the  telescope,  and  clamp  and  tangential 
movement  to  telescope  axis. 

Price $105.00 

Stadia  hairs,  $3.00  extra. 

No.  14. 

The  same  as  No.  13,  with  a  vertical  arc  graduated  to  read  to  minutes. 

Price $118.50 

Stadia  hairs,  $3.00  extra. 

146 


I  UK  A.  LIETZ  COMPANY 
MAKERS, 

SAX   FU.VXCL-SCO,  CAI,. 


No.  15. 
COMPOUND  MINING  AND  SOLAR  INSTRUMENT. 

Price,  $168.50. 

-For  details,  see  the  following  page. 
147 


No.  15. 
COMPOUND  MINING  AND  SOLAR  INSTRUMENT. 

This  instrument  is  like  No.  14,  with  a  Saegmiiller  solar  attachment.  It  pos- 
sesses a  long  center,  horizontal  leveling  screws,  operating  against  a  ball  in  a  socket. 
Xo  horizontal  plate.  Compass  needle  and  graduating  compass  ring,  with  variation 
plate.  Sensitive  plate  levels.  Cloth  finished  standards,  carrying  a  fine  achromatic 
telescope.  The  telescope  is  reversible  and  accurately  balanced.  It  affords  ample 
definiiion,  power  and  light.  May  be  had  with  or  without  stadia  hairs. 

The  solar  attachment  is  screwed  into  the  top  of  the  telescope  axis  and  becomes 
a  part  of  the  instrument.  It  answers  all  the  purposes  of  a  side  telescope,  as  shown 
in  the  marginal  sketch. 

The  whole  instrument  is  packed  in  a  handsome  case,  with  a  special  place  for 
the  solar  attachment,  containing  a  plumb  bob,  adjusting  pins,  and  all  the  usual 
accessories. 

A  light  but  strong  tripod  is  furnished. 

Dimensions  and  Weight. 

Compass  Needle 3%  inches  long. 

Telescope 8 

Object  Glass i  "      diam. 

Vertical  Arc 4  *•*         " 

Magnifying  power 18 

Weight  of  instrument  with  solar  attachment 8%  Ibs. 

tripod 6 

box 4^  " 

The  price  ot  this  instrument  is . .  $168  50 

Stadia  hairs,  $3.00  extra. 

148 


No    16. 
COMPOUND   MINING   AND   SOLAR   TRANSIT, 

Price,  Complete,  $318.00. 

•For  details,  see  the  following  page. 
149 


No.  16. 
COMPOUND  MINING  AND  SOLAR  TRANSIT. 

This  instrument  is  like  No.  4,  with  the  Saegmuller  solar  attachment. 

It  possesses  a  double  center,  lower  clamp  and  tangential  movement ;  plate 
movement  with  clamp  and  tangent  screw,  and  sensitive  plate  levels  ;  double  ver- 
niers reading  to  minutes,  placed  conveniently  for  reading,  without  stepping  from 
the  eye  end.  Compass  needle  and  graduated  compass  ring,  with  variation  plate. 
Cloth  finished  standards,  carrying  an  improved  telescope.  The  telescope  is  revers- 
ible and  evenly  balanced  ;  it  affords  ample  definition,  power  and  light ;  fixed  stadia 
hairs  are  supplied ;  it  has  a  long  level  and  possesses  a  clamp  and  tangential  move- 
ment ;  also  gradient er  attachment ;  a  full  or  half  vertical  circle  reading  to  minutes. 
All  graduations  are  on  solid  silver.  The  instrument  has  the  Lietz  tripod  coupling, 
and  a  shifting  center. 

The  solar  attachment  is  detachable,  screws  into  the  top  of  the  telescope  axis, 
and  becomes  a  part  of  the  instrument.  It  answers  all  the  purposes  of  a  side  tele- 
scope, as  shown  in  the  marginal  sketch. 

The  whole  instrument  is  packed  in  a  handsome  case,  with  a  special  place  for 
the  solar  attachment,  containing  a  plumb  bob,  adjusting  pins  and  all  the  usual 
accessories. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  edge  of  graduation) 6^  inches  diam. 

Vertical  Arc  or  Circle  (measured  to  edge  of  graduation) 5         "  " 

Compass  Needle 4%     "         long. 

Telescope 1 1         "  " 

Object  Glass i}£     "        diam. 

Magnifying  power 24 

Weight  of  instrument 16        Ibs. 

"  tripod 8%     " 

"  box 8     " 

Weight  of  this  instrument,  if  made  of  hard  aluminium. . .   8         " 

The  price  of  this  instrument,  complete,  is $3 18  oo 

And  if  made  of  hard  aluminium,  15%  are  added. 


The  Extras,  for  which  additional  charge  is  made,  are  as  follows: 

Verniers  reading  to  30"  on  horizontal  circle $1000 

"  20"                "              "        2000 

Adjustable  Stadia  Hairs 10  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four. .....  10  oo 

Three  leveling -screw  shifting  center 5  oo 

Prism  attachable  to  eye-piece 8  oo 

Extra  extension  tripod 1 5  oo 

Extension  tripod  in  lieu  of  the  ordinary 5  oo 

Reversion  level  for   telescope  (see  slip  I34A) 10  oo 

Half-length  tripod 13  oo 

Detachable  side  telescope 35  oo 

Lamp  for  mining  engineering,  of  brass,  with  ground  lens 7  oo 

Reflector,  for  illuminating  cross  hairs ; 4  oo 

Plummet  lamp 10  oo 

Large  plumb  bob,  weight,  4  Ibs.,  for  use  in  shafts 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

150 


iiK  A.  LIETZ COMPANY, 

MAKERS, 
HAN  FRANCISCO,  CAL. 


No.  17. 
COMPOUND   MINING  AND   SOLAR  TRANSIT. 

Price,  Complete,  313.00. 

For  details,  see  the  following  page. 
151 


No.   17. 
COMPOUND  MINING  AND  SOLAR  TRANSIT. 

This  instrument  is  like  No.  9,  with  the  Saegmuller  solar  attachment. 
It  possesses  a  double  center,  lower  clamp  and  tangential  movement  ;  plate 
movement  with  clamp  and  tangent  screw,  and  sensitive  plate  levels  ;  double  ver- 
niers reading  to  minutes,  placed  conveniently  for  reading  without  stepping  from  the 
eye  end.  Compass  needle  and  graduated  compass  ring,  with  variation  plate.  Cloth 
finished  standards,  carrying  an  improved  telescope.  The  telescope  is  reversible 
and  evenly  balanced  ;  it  affords  ample  definition,  power  and  light ;  fixed  stadia 
hairs  are  supplied  ;  it  has  a  long  level  and  possesses  a  clamp  and  tangential  move- 
ment  ;  also  gradienter  attachment ;  a  full  or  half  vertical  circle  reading  to  minutes. 
All  graduations  are  on  solid  silver.  The  instrument  has  the  Lietz  tripod  coupling, 
and  a  shifting  center. 

The  solar  attachment  is  detachable,  screws  into  the  top  of  the  telescope  axis, 
and  becomes  a  part  of  the  instrument.  It  answers  all  the  purposes  of  a  side  tele- 
scope, as  shown  in  the  marginal  sketch. 

The  whole  instrument  is  packed  in  a  handsome  case,  with  a  special  place  for 
the  solar  attachment,  containing  a  plumb-bob,  adjusting  pins  and  all  the  usual  ac- 
cessories. 

Dimensions  and  Weight. 

Horizontal  Circle  (measured  to  edge  of  graduation) 5  inches  diam. 

Vertical  Circle  (measured  to  edge  of  graduation) 4       "         " 

Compass  Needle 3%    "      long. 

Telescope 8       "         " 

Object  Glass I        "      diam 

Magnifying  power 18 

Weight  of  instrument 9  Ibs. 

"          tripod 6    " 

box ...  6   " 

Weight  of  this  instrument,  if  made  of  hard  aluminium. ...   5    " 

The  price  of  this  instrument,  complete,  is $3J3  ° 

And  if  made  of  hard  aluminium,  15%  are  added 

The  Extras,  for  which  additional  charge  is  made,  is  as  follows : 

Adjustable  Stadia  Hairs $  I  o  oo 

Arrangement  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Reversion  level  on  telescope  (see  slip  I34A) 10  oo 

Constructed  with  three  leveling  screws  on  base-plate,  instead  of  four 10  oo 

Three  leveling- screw  shifting  center 5  oo 

Prism  attachable  to  eye-piece 8  oo 

Extra  extension  tripod 1 5  oo 

Half-length  tripod 13  oo 

Extension  tripod  in  lieu  of  the  ordinary 5  oo 

Detachable  side  telescope 35  oo 

Lamp  for  mining  engineering,  of  brass,  with  ground  lens 7  oo 

Reflector,  for  illuminating  cross  hairs 4  oo 

Plummet  lamp 10  oo 

Large  plumb-bob,  weight  4  Ibs.,  for  use  in  shafts 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

152 


No.  18. 

CYCLOTOMIC    TRANSIT. 

Patent  applied  for. 

A  single  center  instrument,  admitting  of  every  evolution  that  the  double  center  trniiHt  is  able 
to  carry  out.    (See  Professional  Paper  No.  7,  Part  III.) 
•For  details  and  prices,  see  the  following  pages. 
153 


THE  CYCLOTOMIC  TRANSIT. 

(Patent  Applied  for.) 

This  instrument  has  been  described  and  its  advantages  fully  set  forth,  together 
with  its  use  in  the  field,  in  Part  III,  pages  121-126,  Professional  Paper  No.  7,  to 
which  we  would  now  refer. 

The  instrument  is  first-class  in  every  particular,  and  made  to  correspond  in  all 
details  to  our  high-grade  transits  shown  in  previous  numbers ;  it  is  intended  for 
any  of  the  most  accurate  work  the  engineer  is  called  upon  to  do. 

It  has  but  one  spindle,  but  the  simple  arrangement  of  the  cyclotome 
admits  of  every  evolution  that  the  double  center  is  capable  of  carrying  out. 

Its  invention  is  the  result  of  a  constant  aim  on  our  part  to  create  a  simple  long 
center  instrument,  against  which  it  may  not  be  said  that  the  value  of  a  horizontal 
angle  cannot  be  determined  at  once,  without  taking  two  readings  and  obtaining  a 
calculated  difference. 

The  design  is  novel,  but  several  instruments  have  been  out  in  the  field  for 
months  and  are  giving  absolute  and  perfect  satisfaction. 

The  instrument  contains  the  best  optical  accessories,  the  most  accurate  plate 
divisions,  and  is  guaranteed  to  give  results  to  the  limits  of  its  vernier  graduations, 
which  may  be  had  to  twenty  seconds  of  arc,  if  desired. 

The  high-grade  Cyclotomic  Transit  is  made  in  two  sizes,  of  dimensions  sim- 
ilar to  our  other  transits,  and  these  sizes  are  manufactured  either  in  red  metal  or 
aluminium.  They  are  numbered  1 8  for  the  larger  and  i8a  for  the  smaller  size. 

A  complete  Cyclotomic  Reconnoissance  Transit,  No.  i8b,  is  also  man- 
ufactured, in  which  the  advantages  of  the  system  are  combined  to  make  a  reliable 
instrument,  complete  in  every  detail,  for  any  work  in  the  line  of  modern  engineer- 
ing, at  the  most  reasonable  cost.  See  page  156  for  details. 

We  recommend  the  Cyclotomic  Instrument  to  the  profession.  Its  use  and 
manipulation  are  extremely  simple,  and  the  results  of  its  work  absolutely  reliable. 

Any  special  information,  if  called  for,  will  be  furnished. 

See  testimonials  in  front  on  fly  leaves. 

154 


No.  18. 
COMPLETE  CYCLOTOMIC  TRANSIT. 

(Patent  applied  for.) 
Dimensions  and  Weight. 

Horizontal  circle  (measured  to  edge  of  graduation) 6^  inches  diam. 

Vertical  circle  "  "  "  5  "         •« 

Compass  needle 4%       "      iong. 

Object  glass i%       "    diam. 

Telescope     ..    n  "      long. 

Magnifying  power 24 

Weight  of  instrument 15      Ibs. 

tripod 8%    " 

"  box 8        " 

Weight  of  this  instrument  if  made  of  hard  aluminium .    . .   7%    " 

The  price  of  this  instrument  complete,  as  shown  is $200  oo 

And  if  made  of  hard  aluminium,  15  per  cent  added. 

No.  i8a. 
COMPLETE  CYCLOTOMIC  TRANSIT. 

(The  same  as  No.  18,  but  smaller.) 
Dimensions  and  Weight. 

Horizontal  circle  (measured  to  edge  of  graduation) 5      inches  diam. 

Vertical  arc  or  ci  cle  (measured  to  edge  of  graduation) 4  "         *' 

Compass  needle 3  %       "       long. 

Object  glass r  "      diam. 

Telescope     8  "       long. 

Magnifying  power 18 

Weight  of  instrument 8*4  Ibs. 

tripod 6        " 

box 6 

Weight  of  this  instrument  if  made  of  hard  aluminium.  ..  4^    " 

The  price  of  this  instrument  complete  is $195  °° 

And  if  made  of  hard  aluminium,  1 5  per  cent  added. 

The  Extras,  for  which  additional  charge  is   made  for  either  size,  except 

where  noted,  are  as  follows  : 
Solid  silver  graduations  : 

On  horizontal  circle $1000 

On  vertical  arc  or  circle 5  oo 

Verniers  (horizontal)  reading  to  30"  (No.  18) 10  oo 

"  20"  (No.  1 8) 2000 

Gradienter  attachment 5  oo 

Stadia  hairs,  fixed 3  oo 

"          "     adjustable 10  oo 

Variation  plate 10  oo 

Arrangements  for  offsetting  right  angles 5  oo 

Striding  level  to  axis  of  telescope 20  oo 

Reversion  level  (see  slip  I34A) 10  oo 

Constructed  with  three  leveling  screws  on  base  plate,  instead  of  four 10  oo 

Three  leveling-screw  shifting  center 5  oo 

Prism,  attachable  to  eye-piece 8  oo 

Extra  extension  tripod 15  oo 

Extra  tripod,  in  lieu  of  the  ordinary 5  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

Saegmiiller  solar  attachment  of  aluminium 50  oo 

155 


Fig  1 


Section 


or>     t/r?e     X   -  Center  -  Y, 
with   j/c/e    v/en    of*  7e/e<sco/oe 


PATENTED     MARCH.     1896. 
156 


AH  rinhu  resets  <i. 


THE  A.  LIETZ 

MAKERS 

SAN   FRANCISCO 

CAL. 

PATENTED  MA  HOI,  1 


No.  18b. 
COMPLETE   CYCLOTOMIC   RECONNOISSANCE   TRANSIT. 

Price,  as  shown  complete,  $125  00. 
For  Extras  and  Details    see  the  following  page. 


156a. 


No.  18b. 

COMPLETE  CYCLOTOMIC  RECONNOISSANCE 
TRANSIT. 

(Patented  March  1896.) 

A  field  instrument  of  medium  size,  possessing  a  VERY  LARGE  NEEDLE,  one  hor- 
izontal vernier,  vertical  arc  or  circle,  and  every  accessory  to  make  the  instrument 
a  complete  tachy meter  for  stadia  work.  For  topography  it  has  no  equal  in  sim- 
plicity of  operating  parts,  and  full  equipment  for  work  of  such  character. 

It  admits  of  laying  off  horizontal  and  vertical  angles  correctly  to  one  minute 
of  arc  ;  the  starting  azimuth  may  be  made  zero  or  any  other  reading,  with  as  much 
facility  as  any  other  know  transit,  although  the  instrument  has  only  one  spindle. 
This  spindle  or  center  is  of  extra  large  dimensions  in  length  and  diameter,  which 
affords  great  stiffness  and  rigidity  to  the  whole  structure. 

Dimensions  and  Weight. 

Horizontal  circle  (measured  to  edge  of  graduation) 4  inches  diam. 

Vertical  arc  (or  circle) 4      "         " 

Compass  needle 4/4  "       long. 

Object  glass 7/z  "      diam. 

Telescope 8      "      long. 

Weight  of  instrument 7%         IDS- 

"  tripod 6 

"  box 5 

Weight  of  this  instrument  if  made  of  hard  aluminium 4^  " 

The  price  of  this  instrument,  complete,  is $!25  oo 

And  if  made  of  hard  aluminium,  15  per  cent  added. 

The  Extras,  for  which  additional  charge  is  made,  are  as  follows  : 

Stadia  hairs,  fixed $  3  oo 

Variation  plate 10  oo 

Extension  tripod  in  lieu  of  the  ordinary 5  co 

Protection  bag I  oo 

Bottle  of  tme  watch  oil 25 


*  No.  18c. 

MINING  TRANSIT,  WITH  INCLINED  STANDARDS. 

Built  to  order  from  a  special  design. 
•See  the  following  page. 
157 


No.  i8c. 

This  mining  transit  with  inclined  standards  was  designed  by  C.  S.  Batterman, 
Esq.,  Mining  Engineer,  of  Aspen,  Colorado,  and  built  for  him  by  this  Company. 

The  design  is  a  novel  one,  and  for  Mr.  Batterman's  purpose,  the  instrument 
has  given  full  satisfaction. 

We  are  prepared  to  cnrry  out  any  order  of  a  similar  character.  If  our  cus- 
tomers have  special  designs  for  special  purposes,  we  shall  build  to  their  own  spec- 
ifications, if  so  ordered. 

Prices  will  depend  upon  the  time  consumed,  and  we  are  always  ready  to  fur- 
nish estimates  of  the  probable  cosl. 

Any  communication  will  receive  our  prompt  attention  and  consideration. 


I 

A     a 

Cx]  W) 

E>         | 

f 

,21! 

Oi   »  ^ 

d  as   «  i 

^     (V!       O 


No.  19. 

ENGINEERS'  Y-LEVEL. 

Possesses  all  recent  improvements.  Long  steel  center;  star-shaped  construc- 
tion of  the  guide  for  the  foot-screws  ;  clamp  and  tangential  movement  ;  sensitive 
spirit  level.  The  telescope  has  definition,  light  and  power  in  a  high  degree  ;  best 
achromatic  Jena  glass  lenses  (erect  vision)  and  stadia  hairs  if  desired  ;  is  provided 
with  a  slide-protector,  and  either  cloth,  bright  or  bronzed  finished.  Fastened  to 
the  tripod  by  means  of  the  Lietz  coupling. 

The  whole  is  packed  in  a  neat  case,  containing  all  the  usual  accessories. 

Dimensions  and  Weight. 

Length  of  telescope  .....  ,  ..............................  18      inches 

Diameter  of  objective  ...................................    i;^       " 

Magnifying  power  ...........................  ............  33 

Weight  of  instrument  ...........................  ..........  10^2     Ibs. 

"  tripod  ......................................    .   8 

box  .......................................   7l/2       " 

Weight  of  this  instrument,  if  made  of  hard  aluminium  ........  6^ 

The  price  of  this  instrument  is  ..................................          $'4°  °° 

And  if  made  of  hard  aluminium,  15%  are  added. 

The  Extras,  for  which  additional  charge  is  made,  are  as  follows  : 

Mirror,  to  conlrol  the  bubble  at  eye  end  ........................  .  ......  $1000 

Stadia  hairs,  fixed  ..................................................  3  °° 

"           "     adjustable  ...........................................  10  co 

Agate-fitted  Y's  ..........    ........................................  10  oo 

Reversion  level  to  telescope  (see  slip  I34A  )  .................    ......    ...  1  5  oo 

Three  leveling  screws  on  base-plate,  instead  of  four  ....................  10  oo 

Protection  bag  ...................................  ...............  I  oo 

Bottle  of  fine  watch  oil  .............................................  25 


this  instrument  is  provided  with  a  micrometer  screw  for  the  vertical  control 
of  one  of  the  Y's,  and  an  additional  spirit  level,  set  normal  to  the  line  of  collima- 
tion,  it  becomes  a  HYDROGRAPHIC  Y-LEVEL.  The  charges  for  these  addi- 
tions are  $40.00. 


160 


No.  2O. 

15-IiscH   DUMPY   LEVEL 

"1 

Price,  $90.00. 


No.  20a. 
15-INCH   JDuMP¥   LEYEI 

With  mirror  attachi 
Price,  $100.00. 


With  mirror 

folded  flown 


No.  20a. 

With  mirror  raised. 


IHE  A.  LIETZ  COMPANY 

MAKERS, 
SAN  FRANCISCO,  CAL. 


*The  mirror,  when  folded  down,  serves  as  a  protection  to  the  spirit  level;  when  raised,  it 
indicates  the  position  of  the  bubble  at  the  eye  end  of  the  telescope,  so  that  the  observer  may 
control  it  without  changing  his  position. 

—  -For  details  of  the  Dumpy  Level,  see  the  following  page. 
161 


No.  20. 

ENGINEERS'  DUMPY  LEVEL. 

Long  center  and  most  approved  construction  of  the  lower  parts,  with  slotted 
star.  Sensitive  spirit  level,  placed  over  the  telescope,  to  lower  the  center  of  grav- 
ity. The  telescope  has  definition,  light  and  power  in  a  high  degree  ;  best  achro- 
matic Jena  glass  lenses,  erect  vision  and  stadia  hairs  if  desired.  Is  provided  with 
a  slide  protector  and  cloth-finished.  Fastened  to  the  tripod  by  means  of  the  Lietz 
coupling. 

Packed  in  a  neat  case,  containing  all  the  usual  accessories. 

This  is  an  elegant  instrument,  fit  for  the  best  class  of  surveyors5  work,  and  is 
guaranteed  in  every  detail. 

Dimensions  and  Weight. 

Length  of  Telescope 15    inches. 

Diameter  of  Objective   ...    \y%     " 

Magnifying  power 28 

Weight  of  instrument 9        Ibs 

"  tripod 8         " 

box 5^     " 

Weight  of  this  instrument,  if  made  of  hard  aluminium 4^     " 

The  price  of  this  instrument  is , $90.00 

And  if  made  of  hard  aluminium,  1 5%  are  added. 

No.  2oa. 

Is  the  same  as  No.  23,  but  provided  with  a  mirror  to  indicate  the  position  of 
the  bubble  to  an  observer  at  the  eye  end. 

Price $100.00 

If  made  of  hard  aluminium,  15%  are  added. 

The  Extras  to  Nos.  23  and    24,  for    which    additional    charge  is  made, 

are  as  follows  : 

Stadia  Hairs,  fixed 3  oo 

Horizontal  Circle,  reading  to  minutes 25  oo 

Protection  bag I  oo 

Bottle  of  fine  watch  oil 25 

162 


THE  GERMAN  LEVEL  AND  POCKET  SURVEYING  INSTRUMENT. 


For  many  purposes  where  great  accuracy  is  not  required, 
it  is  often  far  more  convenient  to  use  some  small  instrument 
that  will  admit  of  measurements  within  practical  limits.  The 
irrigator,  farmer,  ditcher,  grader,  building  contractor,  gardener, 
forester,  road  builder,  etc.,  often  require  means  of  obtaining 
heights  and  relative  positions,  for  which  a  higher  grade  instru- 
ment would  be  unnecessarily  refined. 

It  is  for  the  use  of  such  men  that  we  have  imported  a  lev- 
cling  apparatus,  patented  in  Germany,  that  combines  portability 
with  accuracy  and  reliability,  within  reasonable  limits,  at  a 
minimum  expenditure.  Such  an  instrument  we  now  offer  for 
sale.  Specimens  of  it  are  shown  on  page  165.  It  offers  an  ad- 
vantage in  this,  that  bubble,  cross-hairs  and  image  may  be 
viewed  at  the  same  time,  for  the  bubble  is  not  controlled  from 
the  outside,  as  usual  in  nearly  all  instruments,  but,  as  in  the 
case  of  a  hand  level,  is  regulated  by  looking  through  the  tube, 
and  adjusting  it  to  the  center  by  raising  or  depressing  the  tele- 
scope. (This  holds  good  for  all,  except  No.  24  which  is  a 
small  dumpy  level.)  The  magnifying  eye-lens  increases  the 
size  of  the  bubble  several  times,  so  that  it  may  be  accurately 
brought  to  the  middle  of  the  field.  The  instrument  is  made 
very  compact,  while  its  manipulation  is  so  simple  that  anyone 
will  be  able  to  use  it  after  a  short  practice. 

The  level,  when  packed  in  a  leathern  case,  may  be  easily 
put  in  the  coat  pocket. 

The  instrument  consists  of  a  terrestrial  telescope,  having 
u  magnifying  power  of  from  10  to  15;  an  achromatic  objective; 
and  an  appropriate  eye-piece,  allowing  an  extension  of  the  eye- 
tube,  with  room  sufficient  to  attach  the  level  case  underneath  it. 

The  instrument  may  be  screwed  into  any  support,  like  a 
heavy  walking  stick  or  a  Jacob's  staff,  but  we  make  for  it  a  light 
tripod  for  convenient  use.  The  ball  and  socket  movement,  just 
below  the  standard,  admits  of  clamping  in  an  upright  position, 
so  that  the  telescope  axis  may  be  placed  approximately  in  a 
horizontal  plane  before  finer  adjustment  is  made 


164  MODERN    SURVEYING    INSTRUMENTS. 

The  focus  is  regulated  by  a  motion  of  the  eye-piece,  and 
extension  tube  respectively.  The  former  is  pulled  out  far 
enough  to  make  the  cross-wires  plainly  visible;  the  tube  is  ex- 
tended until  the  image  becomes  clear  and  distinct,  and  remains 
stationary  with  the  cross-hairs,  when  the  eye  is  moved  from  side 
to  side  in  front  of  the  eye-piece,  insuring  a  freedom  from  all 
parallax. 

In  the  tube  is  placed  a  mirror  at  an  angle  of  45  degrees,  hav- 
ing a  circular  opening  in  the  middle,  behind  which  the  cross- 
hairs are  located.  Under  the  mirror  lies  the  level  vial,  which 
is  adjustable  by  two  small  screws.  By  means  of  an  opening  in 
the  bottom  of  the  case,  light  is  admitted  through  the  vial  to  the 
glass,  and  when  the  telescope  is  brought  into  a  horizontal  posi- 
tion, the  bubble  is  seen  standing  vertically  in  the  mirror  by 
looking  through  the  eye-end;  and  through  the  opening  in  the 
mirror  appear  the  cross-hairs  and  the  image.  To  obtain  the 
horizontal  position  of  the  telescope,  the  large  screw  head  at  the 
objective  end  and  below  it  is  turned  either  up  or  down,  until 

the  reflected  bubble  is  brought 


,MIRROR 


REFLECTED  BUBBLE         to  appear  evenly   above   and   below 
CROSSHAIRS  the  field  of  the  cross-hairs,  which 

is    readily   done  by    the   eye   (see 
LEVEL  BUBBLE  marginal  figure).     At  every  turn 

of  the  instrument  in  a  horizontal 
plane    the    bubble    must    be     re-i 
Section  of  Level  Telescope  adjusted  as  described. 

Attention  is  called  to  the  fact  that  it  is  of  advantage  to 
bring  the  eye  as  closely  as  possible  to  the  tube,  so  that  the  sur- 
face of  the  mirror  may  be  in  full  view  through  the  eye-lens.  In 
case  the  instrument  is  used  in  a  closed  room,  where  the  floor  is 
dark,  the  bubble  must  be  illuminated  by  holding  under  it  a 
piece  of  white  paper  or  some  light  object. 

Combinations  are  made  and  kept  in  stock,  wherein  this 
level  is  supplied  with  an  azimuth  compass,  so  that  directions 
may  be  obtained  as  well.  The  higher-class  combinations  have 
a  graduated  plate,  and  admit  of  reading  the  horizontal  angle 
to  one  minute  of  arc.  They  are  also  supplied  with  a  vertical 
arc  and  with  stadia  hairs  set  1  :  100  so  that  the  instrument  be- 
comes a  little  theodolite  for  manifold  purposes. 


GERMAN  LEVEL  AND  POCKET  SURVEYING 

INSTRUMENT. 

No.  21. 

Instrument  mounted  on  strong  tripod  ;  ball  and  socket  movement  with  clamp  ; 
horizontal  movement  with  clamp  and  tangent  screw  ;  needle  and  compass,  the  ring 
graduated  to  degrees  ;  telescope  adjustable  to  focus  ;  achromatic  objective  ;  adjust- 
able eye-piece ;  the  level  bubble  is  viewed  in  the  field  like  a  Locke's  hand  level, 
the  whole  is  packed  in  a  neat  wooden  case. 

Dimensions  and  Weight. 

Length  of  telescope , .   8      inches 

Diameter  of  objective ^i       " 

Length  of  compass  needle 2^i       " 

Magnifying  power 10 

Weight  of  instrument 2       Ibs. 

Price  of  this  instrument,  with  tripod — $25  oo 

Stadia  hairs $3  oo  extra 

Small  plumb  bob I  oo     " 

No.    22. 

Is  like  No.  21,  but  instead  of  the  compass  it  has  a  3-inch  horizontal  circle, 
with  a  vernier  reading  to  minutes.  The  whole  is  packed  in  a  fine  morocco  pocket 

case. 

Price,  with  tripod $30  oo 

Stadia  hairs $3  oo  extra 

Small  plumb  bob i  oo     " 

No.  23. 

Is  like  No.  21,  and  in  addition  possesses  a  3  inch  vertical  arc.  Packed  in 
neat  wooden  case. 

Price,  with  tripod $35  °° 

Stadia  hairs $3  oo  extra 

Small  plumb  bob I  oo     " 

No.  24. 

This  is  a  small  dumpy  level  of  firm  and  substantial  construction.  It  has  lev- 
eling screws  with  opposing  springs,  operating  through  a  star,  suspended  over  the 
center.  Provided  with  a  horizontal  circle,  with  vernier  reading  to  minutes.  The 
telescope  is  adjustable  to  focus  ;  achromatic  objective,  with  protection  cap  ;  ad- 
justable eye-piece  ;  the  4-inch  spirit  level  is  mounted  on  top  of  the  telescope. 
Packed  in  a  neat  wooden  case,  with  the  usual  accessories. 

Dimensions  and  Weight. 

Length  of  telescope 10      inches 

Diameter  of  objective fa 

Diameter  of  horizontal  circle 4 

Magnifying  power i 5 

Weight  of  this  instrument 3       11)S- 

Price,  with  tripod $40  oo 

Stadia  hairs $3  °° 

166 


THE    A.    LIETZ    COMPANY. 


167 


Its  cost  is  within  the  reach  of  all,  and  we  know  of  no  pres- 
ent better  adapted  to  the  young  student,  than  one  of  these 
complete  little  field  instruments,  with  which  so  much  can  be 
accomplished,  and  so  much  can  be  learned.  Every  manipula- 
tion of  the  theodolite  is  represented  here,  and  it  admits  of  obtain- 
ing results  approaching  those  of  the  ordinary  land  surveyor's 
compass  and  level. 

Crude  instruments  are  placed  on  the  market  to  supply  the 
demand  for  a  fairly  reliable  measuring  tool  at  small  cost;  these 
are  usually  worthless,  as  they  are  made  without  any  regard  for 
the  underlying  principles  that  should  govern  the  make  of  such 
an  article.  But  with  our  German  pocket  instrument,  which  is 
protected  by  letters  patent  in  the  Empire,  the  object  has  been 
attained.  It  is  perfectly  reliable  within  the  scope  for  which  it 
was  intended.  Every  part  is  carefully  made  and  nicely  finished, 
and  its  cost  is  less,  in  comparison,  than  the  inferior  article  that  is  usu- 
ally offered  for  sale  in  the  market. 


No.  25. 
COMPLETE  POCKET  INSTRUMENT. 

Telescope  is  now  mounted  on  the  outside  of  the  Stnndard. 
Price,  with  stadia  hairs  and  tripod,  complete,  $58.00. 


No.  26. 
SEISMOGRAPH. 

Registers  both  components  of  the  shock  motion,  horizontal  and  vertical. 

An  improved  and  simplified  instrument,  suggested  by  E.  Brassart,  of  the  Geodynamic 
Institute  of  Rome. 

Information  furnished  upon  application.     Instruments  of  this  character  are  built  to 
order. 

1 68 


169 


PLANE  TABLES. 
No.  27. 

This  is  the  style  used  in  the  topographical  work,  of  the  U.  S.  Coast  and 
Geodetic  Survey,  containing  all  the  parts  necessary  for  a  proper  equipment  of  the 
table,  and  an  alidade  of  the  most  approved  pattern.  The  table  is  so  made  that  a 
change  from  temperature  or  humidity  is  impossible.  Its  dimensiors  are  about  24 
inches  square.  The  telescope  is  achromatic,  and  of  sufficient  power  for  accurate 
stadia  measurement ;  the  stadia  hairs  are  always  supplied.  It  may  be  eitlureiect 
or  inverting.  It  is  furnished  ^ith  a  vertical  arc  and  an  accurate  striding  levi  1. 
The  table  has  a  plumbing  bar,  and  the  alidade  a  box  compass  and  a  circular  K-vel. 
Furnished  with  an  elegant  case. 

Dimensions. 

Size  of  table , 24  inches  square 

Length  of  ruler '. 21  " 

Length  of  needle  in  box 4  " 

Lengi  h  of  telescope 15  • ' 

Radius  of  vertical  arc ^l/2  ' ' 

Magnifying  power 32  " 

The  price  of  this  instrument  complete  as  described  and  shown 

on  plate,  is $300  oo 

No.  aya. 

An  improved  table  and  alidade,  the  latter  either  of  brass  or  aluminium,  as 
used  in  the  topographical  work  of  the  Geological  Suivey  ;  the  alidade  having  been 
especially  designed  |nr  mountain  survevs  by  the  able  officers  of  that  department. 
Everything  is  made  \\ith  a  view  to  insure  compactness.  Supplied  with  all  the 
necessary  accessories. 

Price,  complete,  with  br»ss  alidade $300  oo 

With  aluminium  alidade 330  oo 

170 


•SaSS-SsI.-"8 

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THK  A.  LIET/  COMPANY, 

MAKKRS, 
SAN  FKANCISCO.  CAI.. 


Nos.  29  to  31. 

RANGING    POLES. 

Price.  $3.7510  $3.00. 

details  on  the  following  page,  and  marginal  note  on  this  page. 
171 


LEVELING  RODS. 
No.  28 

Philadelphia  self-reading  rods,  with  vernier,  clamps  and  target,  reading  to 
loooths  ;  from  6  to  8  feet  long.  Slides  out  to  13  feet. 

Price $16  oo 

No.  28a. 

Mining  rod,  3  feet  long,  sliding  out  to  5  feet,  with  vernier  clamps  and  target, 
reading  to  loooths. 

Price $13.50 

RANGING  POLES. 
No.  29. 

Wooden  pole,  6  and  8  feet  long,  with  steel  pointed  shoe,  divided  in  feet,  red  a.id 
white  alternately. 

Each $2.25 

No.  30. 

Octagonal  steel  spear,  6  to  8  feet  long,  divided  in  feet,  red  and  white  alter- 
nately. 

Each $275 

No.  31. 

Of  half-inch  iron  pipe,  wilh  pointed  steel  shoe,  divided  in  feet,  red  and  white 
alternately. 

Each $2-75 

FLEXIBLE  RODS. 

No.  32. 

FOR  LEVELING  AND  STADIA  WORK. 

Painted  on  either  heavy  or  light  canvas,  with  a  legible  design  to  read  to  hun- 
dredths  of  a  foot.  The  numerals  of  the  tenths  are  black  and  one-tenth  of  a  foot 
high  ;  the  foot  numerals  are  red  and  two-tenths  of  a  foot  high.  Length,  IO  or  12 
feet.  May  be  rolled  up  in  a  package  2j£  to  3  inches  long  (the  width  of  the  can- 
vas), and  less  than  i^  inches  in  diameter,  weighing  less  than  3  ounces.  A  very 
handy  requisite  on  a  long  trip. 

Price,  10  feet  long $3  oo 

"      12     "      "    3  25 

172 


No.  33  f- 
EQUATORIAL. 

9-inch  aperture ;  focal  length,  n'  10" 

(See  the  following  page.) 
( f  See  introduction  to  Part  IV.) 


EQUATORIAL   REFRACTORS. 

Improved  mounting  upon  a  rectangular  pillar,  containing  the  strong  driving 
clock. 

All  necessary  adjustments  and  manipulations  possible  from  the  eye-piece. 

The  telescope  possesses  a  number  of  astronomical  and  micrometer  eye-pieces, 
varying  in  power  with  the  size  of  the  instrument,  from  40  to  1200. 

The  diameter  of  the  aperture  varies  from  3i  inches  to  12  inches,  and  the  focal 
length  from  4  feet  5  inches  to  15  feet  9  inches. 

Has  one  or  two  ring  micrometers,  the  declination  circle  reading  to  5  seconds  of 
arc,  the  lionr  circle  to  2  seconds  of  time. 

The  finder  has  an  aperture  of  from  2  to  3  inches. 

The  smaller  sizes  may  be  had  with  or  without  driving  clock. 

All  the  necessary  accessories  are  supplied. 

We  invite  correspondence  on  this  subject,  and  will  furnish  prices  upon  appli- 
cation. 


PORTABLE 

MERIDIAN    INSTRUMENTS. 

(\Vith  rectangular  prismatic  telescope.) 

The  lower  frame  of  these  instruments  is  of  cast  iron,  containing  a  mechanical 
device  for  rapidly  reversing  the  axis,  without  removing  the  spirit  level.  Graduated 
circle  at  the  eye-end  of  the  axis.  Micrometer  eye-piece;  adjustable  central  illumi- 
nation of  the  field  through  the  axis,  the  latter  balanced  on  friction  rollers.  Adjust- 
able in  azimuth.  Furnished  with  a  number  of  eye-pieces,  varying  with  the  size  of 
ihe  instrument;  the  power  ranging  from  48  to  160. 

The  diameter  of  the  circle  may  reach  10  inches,  and  the  distance  between  bear- 
ings, 25  inches. 

These  instruments  are  made  in  different  sizes,  the  diameter  of  the  aperture 
varying  from  2J  to  3  inches,  and  the  focal  length  from  25  to  38  inches. 

All  necessary  accessories  supplied. 

Correspondence  invited  and  detailed  prices  furnished  upon  application. 

i74 


No.  34  f- 
MERIDIAN    INSTRUMENT. 

With  rectangular  prismatic  telescope,  eye-piece  at  axis.     2%-inch  aperture, 
focal  length,  33  inches. 


(,See  the  opposite  pagej 

175 


No.  35. 
ALT-AZIMUTH   INSTRUMENT. 

Circles  11  inches  in  diameter.  Micrometer  microscopes,  reading  to  seconori 
direct;  with  additional  reading-glasses  to  verniers.  Telescope  has  an  aperture  01 
If  inches,  and  a  focal  length  of  20|  inches.  Power,  40  and  CO. 

Auxiliary  telescope  with  ejre-piece  micrometer  as  shown.  May  be  clamped  to  the 
iron  ring  of  the  base,  upon  which  it  slides.  The  ej'e-pieces  of  the  telescopes  are 
interchangeable. 

All  accessories  furnished. 

Complete  in  two  tine  packing  cases. 

Different  sizes  are  made  of  the  same  style  at  different  prices. 

Correspondence  is  invited,  and  detailed  information  will  be  furnished  upon 
application. 

Note. — These  alt-azimuths  are  elegant  instruments,  which  are  a  specialty  of 
the  manufacturing  tirni.  The  general  construction  and  the  shape  is  that  of  Pistor 
&:  Martin,  but  a  number  of  recent  improvements  have  been  added  by  the  present 
makers,  so  that  the  instrument  is  an  absolute  standard  in  every  particular.  The 
graduations  are  made  with  great  precision  on  a  dividing  engine  one  meter  in  diam 
eter. 

We  recommend  these  instruments;  they  have  a  Kuropeaii  reputation,  and  are 
not  excelled  by  any  other  make. 

176 


No.  35  f- 

ALT-AZIMUTH    INSTRUMENT, 

With  auxiliary  telescope. 

1 1 -inch  circles. 

Prices  furnished  upon  application. 
I  See  opposite  page.) 

177 


No.   36f. 
ALT-AZIMUTH    INSTRUMENT. 

Circles  7  inches  in  diameter.     Microscopes  read  directly  to  5  seconds. 
Telescope,  1 3-inch  focal  length  and  1%-inch  aperture.     Po-.ver,  25  and  36. 

Prices  furnished  upon  application 


No.    37t- 
ALT-AZIMUTH   INSTRUMENT. 

Circles,  5^  inches  diameter,  verniers  read  to  10  seconds  with  reading-glasses.  Tel- 
escope has  a  focal  length  of  9^  inches  and  a  i  %"-inch  aperture  Power,  20  and  30.  Ad- 
justable eye-piece.  Striding  level  and  level  to  vertical  limb.  Reversible  axis. 

Prices  furnished  upon  application. 
179 


THEODOLITES  WITH  MICROMETER -MICROSCOPES. 

The  horizontal  circle  is  read  by  two  opposite  microscopes  directly  from  1  to  5 
seconds;  its  diameter  varies  from  7  to  14  inches.  The  vertical  circle  has  a  diameter 
of  from  5£  to  9f  inches;  it  is  read  by  two  opposing  verniers  that  indicate  5  or  10 
seconds.  This  circle  may  be  omitted.  The  telescope  may  be  either  in  the  middle 
or  at  the  side;  axis  reversible. 

The  dimensions  and  optical  powers  of  the  telescope  vary  within  the  same  limits 
as  in  the  case  of  the  preceding  alt-azimuth  instruments.  Striding  level  for  telescope 
and  fixed  level  for  horizon. 

Packed  in  two  eases. 

Price  varies  with  the  size  and  the  accessories  desired. 

We  invite  correspondence  and  will  furnish  figures  upon  application. 

The  instruments  are  of  the  highest  grade. 

180 


No.  38 1- 

THEODOLITE  WITH  MICROMETER -MICROSCOPES. 

Horizontal  circle,  8%   inches  diameter.      Both  microscopes  read  5  seconds  direct. 
Striding  level  to  telescope, 

May  be  had 

With  vertical  circle,  6^  inches  diameter,  reading  to  10  seconds,  by  double  vernfers, 
Prices  furnished  upon  application. 

(See  the  opposite  page.) 
181 


No.    39  f- 


REFLECTING    CIRCLE, 

MOUNTKI)  ox  A  BRASS  STAND. 

Has  two  prisms.  Circle,  10^  inches  diameter,  with  two  verniers  reading  10  seconds. 
Measures  angles  from  o  to  360°,  which  is  made  possible  by  the  peculiar  shape  of  the 
prisms.  Provided  with  three  pairs  of  colored  shades.  Telescope  has  an  aperture  of  K 
inch,  with  two  astronomical  eye-pieces;  power,  6  and  10;  and  one  terrestrial  eye-piece 
of  3.  Prismatic  eye -piece,  etc. 

Prices  furnished  upon  application 
182 


No.   40  f. 


REFLECTING  CIRCLE, 

FOR  NAUTICAL  PURPOSES. 

Diameter,  10  inches.  Complete  with  telescope,  having  two  astronomical  eye-pieces. 
Verniers  reading  to  10  seconds.  Measures  angles  from  o  to  288°.  Prismatic  eye-piece. 
Three  pairs  of  colored  shades. 

Complete  with  brass  stand  and  lamp  for  night  observation. 


These  REFLECTING  CIRCLES  and  SEXTANTS  are  made  in  great  variety  as  to  size 
and  style. 

Correspondence  is  solicited  and  prices  will  be  furnished  upon  application. 

183 


AMSLER'S  PLANIMETER, 

(IN  GERMAN  SILVER) 

Arranged  for  Measuring  Areas  in  either  A\etric  or  English  Units. 
Price,  $30.00. 


We  also  keep  in  stock  another  form,  in  which  the  indicator  is  entirely  open  from  above, 
and  not  concealed  by  the  bar  of  the  tracer,  as  in  the  design  shown  in  No.  41,  at  the  same 
price. 

This  very  useful  instrument  for  obtaining  areas  is  so  well 
known  to  the  engineer  that  it  need  not  be  described  in  particu- 
lar. A  theoretical  discussion  of  the  principles  underlying  its 
operation  will  be  found  in  almost  any  handbook  on  higher  sur- 
veying. 

Instructions  how  to  use  it  are  published  by  Amsler,  which 
are  given  below: 

^'Adjust -the  eliding- tube  on  the  bar  HO  that  the  index  mark  on  the  tube  coi?i- 
c-ides  with  one  of  the  marks  on  the  bar.  The  unit  of  area  is  engraved,  to  the  right 
of  the  corresponding  mark.  Then  proceed  as  follows: 

"Needlepoint  outside  the  diagram. — Put  the  instrument  on.  the  drawing  surface 
with  the  tracing  point  at  a  mark  on  the  curve,  the  area  of  which  is  to  be  measured, 
press  the  needle-point  slightly  into  the  paper  outside  the  curve  and  read  off  the 
rolling  wheel  and  the  counting  disk,  taking  the  whole  circumference  of  the  recording 
roller  as  the  unit  of  reading.  (The  roller  need  not  be  set  to  zero.)  Then  move  the 
pointer  (or  tracer)  around  the  area  in  the  direction  of  the  movement  of  the  hands  of 
a  watch,  and  when  you  reach  the  starting  point  take  a  reading.  Subtract  the  first 
from  the  second  reading,  and  multiply  the  remainder  by  the  coefficient  of  the  scale. 

"Example:  Area  required  in  square  feet.  Slide  the  tube  on  the  bar  so  (hat 
the  index  of  the  former  coincides  with  the  mark  denoted  by  0.1  square  ft.  Sup- 
pose the  dimensions  of  the  diagram  allow  the  needle-point  to  be  placed  outside. 
Then 

Second  reading  (say)  8.311 
First      reading  (say)  2.322 


5.9^9  X   0.1   —  0.^939  square  feet. 

"Needle  point  inside  the  diagram.— Circumscribe  the  diagram  with  the  pointer 
in  the  direction  of  the  movement  of  the  hands  of  a  watch,  observing  at  the  same 
time  the  counting  disc,  in  order  to  see  whether  the  total  rotation  is  a  forward  or  a 
backward  motion. 


THE    A.    LIETZ    COMPANY.  185 

' '  This  preliminary  rough  operation  completed,  proceed  as  before  explained,  now 
following  the  curve  carefully  with  the  pointer.  If  the  total  rotation  of  the  roller 
has  been  &  forward  motion,  subtract  the  first  reading  from  the  second,  and  add  the 
difference  to  the  figure  engraved  on  the  top  of  the  bar  just  over  the  mark. 

Thus,  in  a  similar  example: 

Second  reading 5 . 423 

First  reading 3.004 

2.419 

Figure  on  top  of  bar  20.741 


23.160  X  0.1  =  2.316  square  feet. 
The  figures  011  the  top  of  the  bar  are  slightly  different  for  different  instruments. 

"  If  the  total  rotation  of  the  roller  is  a  b«ck  motion,  subtract  the  second  reading 
from  the  first  reading,  and  subtract  the  difference  from  the  figure  on  the  bar. 

"  Note:  When  the  mark  0  on  the  roller  is  at  the  mark  0  of  the  vernier,  a  mark 
of  the  counting  disc  should  be  opposite  the  fixed  index  mark.  Any  slight  non- 
coincidence  due  to  play  between  roller  and  disc  may  readily  be  allowed  for  in  taking 
readings." 

The  engineer  finds  this  instrument  most  useful  in  deter- 
mining the  areas  of  profiles  drawn  upon  cross-section  paper, 
and  it  is  there  nearly  always  the  case  that  the  needle-point  is 
placed  outside  of  the  diagram. 

These  profiles  are  generally  drawn  on  an.  exaggerated  scale, 
the  vertical  scale  being  considerably  larger  than  the  horizontal 
one. 

The  best  means  of  obtaining  the  area  of  such  a  profile  is 
to  draw  a  rectangular  figure  on.  the  same  scale,  or  scales,  of  a 
known  area;  to  circumscribe  that  area  with  the  planimeter  set 
arbitrarily,  but  well  fastened  so  that  the  bar  cannot  slip,  and  to 
read  the  disc,  roller  and  vernier.  The  starting  point  may  have 
been  0  or  not;  in  the  latter  case  we  note  the  difference. 

The  figure  may  be  circumscribed  several  times  and  the 
mean  taken,  should  we  desire  greater  accuracy.  Knowing  the 
area  of  this  rectangular  figure,  it  is  an  easy  matter  to  compare 
it  with  the  reading  of  the  planimeter,  and  to  find  a  coefficient 
by  which  every  planimeter  determination  of  the  area  of  any 
profile  drawn  on  the  same  scale,  or  scales,  of  the  test  figure 
must  be  multiplied  to  give  the  true  result  in  square  units  rep- 
resented by  the  scale.  This  is  so  apparent  that  it  need  not  be 
demonstrated.  It  is  by  far  the  safest  method,  as  it  will  recog- 
nize not  only  scale  exaggeration,  but  any  inaccuracies  in  the 
divisions  of  the  cross-section  paper.  If  we  want  to  be  very 
precise,  we  may  determine  a  coefficient  for  every  sheet  of  the 
cross-section  paper  used. 

The  instrument  we  keep  in  stock  is  Amsler's  Planimeter, 
No.  4  (German  Silver),  price  $30;  but  we  will,  upon  order, 
procure  for  our  customers  any  one  of  the  highest  grade  plani- 
meters,  or  Integrators  for  measuring  areas,  moments  and  mo- 
ments of  inertia.  We  invite  correspondence  on  this  subject. 


SURVEYOR'S  COMPASS. 

No.  42.     The  instrument  has  a5£-inch  needle,  14-inch  plate,  open  sights,  in 

box  with  strap $45  00 

}?o.  43.     The  same  with  variation  plate 50  00 


No.  44. 

No.  44.     Prismatic  Compass,  3  inches  diameter,  with  divided  ring  on  needle 
and  folding  sights;  packed  in  neat  case,  very  convenient  forrecoii- 

ooissance $15  00 

These  Compasses  range  between  &15  00  and  $48  00. 

186 


No.  44a.     Pocket  Compasses,  with  folding  sights,  varying  in  price  from.  .  $6  oo  to  $25  oo 

No.  44b.      Small  Pocket  Compasses,  with  or  without  sights,  ranging  in 

price  from i  oo  to       8  oo 

No.  45.     Miner's  Compass,  or  Dipping  Needle.     An  instrument  for  determin- 
ing the  location  of  iron  by  means  of  a  magnetic  needle.     Price. . .  .$14  00 

No.  46.     Prospector's  Pocket  Balance,  for  making  a  field  analysis  of  minerals. 

Price  ..  ..$12  00 


No.    47- 

No.  47     Locke's  Hand  Level,  with  prism ; £8  00 

Xo.  48     Locke's  Hand  Level,  with  plated  mirror  v 5  CO 

Xo.  49      Abney's  Reflecting  Level  or  Pocket  Altimeter,  improved,  with  divided 

arc  to  show  gradients,  in  morocco  case,  each 15  00 

Xo.  50       Abney's  Reflecting  Level  or  Pocket  Altimeter,  with  bar  needle,  com- 
pass and  socket  for  Jacob  staff ,. 18  00 

Nos.  51 -to  52  German  Telescopic  Hand  Levels  and  Altimeters,  from  .  .  . .  $10  oo  to  20  oo 

ROD    LEVEL. 

No.    53       Level,  for  plumbing  a  rod  or  a  sight-pole,  m'ade  to  fit  the  edge  of  a 

rod  or  pole $3  50 

187 


188 


ILLUMINATING   LAMPS. 

No.  50.     Lamp  for  illuminating  graduations,  cross-wires,  etc.,  for  use  in  un- 

tlergrouml  work,  common §  4  00 

No.  57.     Lamp  of  brass,  with  ground  lenu 7  00 

No.  58.     Small  Plummet  Lamp  of  brass,  steel  point 8  00 

No.  50.     Large         "  "  "  1000 

59a.   Plumb  Bobs  of  the  most  improved  shape  and   of   any  desired  size  and 

weight,  from $1  00  to  $5  00 


SURVEYOR'S  CHAINS. 

No.  GO.     Iron  Chain,  brass  handles,  No.  8  wire,  33  feet $  2  60 

"61.               "                     "                     "         "     50    "   '. 325 

"62.               "                     "                     "         "     66    "   4  00 

"63.               "                     "                     "         "  100    "   5  25 

"    64.     Steel  Chains,        "                 No.  10    "     33    "   350 

"65                "                                           "         "     50    " 4  25 

"66.               "                     "                     "         "     66    "   6  50 

"67.               "                     "                     "         "  100    "   8  00 

"    68.     Steel  Chains,  brazed  links  and  ring,  No.  12  wire,   33  feet 5  50 

««    69.               "                           "                 "               "           "        50     " 6  00 

««    70.               "                                                           "                    66    "   10  00 

««    71.                "                            "                                   "           "       100    "    11  50 


CHAIN   PINS  AND   MARKERS. 

No.  72.    Steel  Arrows,  ll  iu  a  set §1  50 

No.  73.     Marki  ng  Tool,  timber  scribe  for  surveyor's  use 1  25 

iS9 


The  following  tape-lines  take  the  place  of  our  former  catalogue  num- 
bers from  74  to  106  inclusive. 

Paine's  Patent  Standard  Steel  Tapes. 

X  INCH  WIDE. 

In  iron  cases,  brass  bound,  morocco  covered,  improved  handle. 

All  orders  for  steel  tapes  will  be  filled  marked  in  loths  unless  otherwise  directed.  These 
tapes  are  marked  in  links  on  the  other  side,  if  so  ordered. 


Manufacturer's  Number. ...     204  205  206  207  208  209 

Feet 25  33  50  66  75  100 

Price,  each $2.65  3.40  4.50  6.00  7.50  9.00 

These  tapes  are  detachable  from  the  case,  and  are  furnished  with  detachable  rings  to 
avoid  breakage. 

Graduated  Compensating  Handles. 

FOR  VARIOUS  TEMPERATURES. 

Per  pair $2  25 

Pocket  thermometers,  each ,    I   15 

Grummon's  balance  and  level,  each '. 3  oo 

Steel  Spring  Tapes,  German  Silver  Cases. 

Graduated  in  roths  or  I2ths. 


Description.  Price,  Each. 

Manufacturer's  No.  220.     3-foot  steel  tape,  X  i"0'1  wide $i  oo 

"       221.       4  "  "  "  "         I    15 

"  "      222.       5  "  ''*  "  "         I    30 

"  "     223.     6         "  "  " I  40 

"     224.     8         "  "  "  "      '.....    i  60 

44  "      225.    12  "  "  «'«  "        225 

li  "       226.     15  '•  '«  "  " , 265 

IpO 


Eddy's  Improved  Standard  Steel  Tapes. 
IN  LEATHER  COVERED  CASES,  FLUSH  HANDLE. 


Metal-lined  with  flush  handles,  graduated  in  loths  or  I2ths  of  a  foot  or  metric  measure. 

Manufacturer's  Number 210  21 1  212  213  214 

Feet 33  50  66  75  100 

Price,  each $4.15  6.00  7.50  9.00  11.25 

Y%  INCH  WIDE  IN  RED  LEATHER  COVERED  CASES. 

Manufacturer's  Number 300  301           302           303           304  305  306 

Feet 25  33            40            50            66  75  100 

Price,  each $3.75  4.15         5.25          6.00         7.50  9.00  11.25 

YZ  INCH  WIDE  IN  RED  LEATHER  COVERED  CASES. 

Manufacturer's  Number 400  401           402           403           404  405           406 

Feet 25  33             40             50            66  75           100 

Price,  each $4.15  4.50          5.65          6.75         8.25  975  12. oo 

Metallic   Warp  Tapes. 

These  tapes  are  made  of  the  best  linen  tape,  with  wire  threads  to  prevent  stretching, 
and  by  our  process  of  making  are  always  soft  and  pliable.  The  ends  are  reinforced  with 
leather  to  prevent  wearing,  and  all  the  cases  have  our  new  improved  flush  handle.  Gradu- 
ated in  loths,  with  links  on  opposite  side. 


METALLIC  TAPE,  ft  INCH  WIDE. 

Manufacturer's  Number 137           138  139           140           141            142           143 

Feet 25            33  40             50            66            75           100 

Price,  each $1.40          1.60  1.80         2.00         2.40          280          3.20 

191 


We  herewith  present  to  the  profession  a  new  steel  tape  which  is 
intended  to  fill  a  long-felt  want.  A  cheap  but  accurate  and  reliable 
steel  tape.  The  line  is  made  of  the  best  steel,  marked  and  finished  in 
the  best  style  and  mounted  in  a  brass  case,  handsomely  nickel-plated. 
It  is  light  and  durable,  and  easily  carried  in  the  pocket,  and  having  an 
improved  new  handle,  winds  freely. 

Send  for  a  4-inch  sample  piece  of  the  tape. 

When  ordering,  state  if  divisions  in  loth  or  I2th  are  desired. 


Star  Steel  Tapes—  y%  in.  wide. 

Our  Number,  107.  —  Manufacturer's  Number,  500.       50  feet  .................  each  $3  40 

"  "         501.       66  feet  ..................  each     415 


108.  — 
109  — 
1  10.  — 


502.  75  feet  ..................  each     4  50 

503.  100  feet  ..................  each     600 


192 


No.  in. 
STEEL  STANDARD  TAPES. 

Made  of  heavy  steel,  3-16  inch  wide,  with  brass  graduations  ;  only  used  tor  rough  work. 

For  each  100  feet  of  tape $i  oo 

For  each  graduation 15 

Pair  of  clamping  handles .  .    3  oo 

Wooden  reel 3  oo 


193 


SEXTANTS. 

No.  112.  Sextant  of  gun  metal,  light,  but  very  strong,  7-inch  radius,  120 
degrees,  graduated  on  silver  to  10  minutes,  vernier  reading  to  10  seconds, 
2  astronomical  telescopes  magnifying  6  and  10  times.  1  terrestrial  tele- 
scope, object  glass,  1$  in.,  seven  neutral  glasses  and  two  reflecting 
mirrors.  Instrument  complete  in  polished  mahogany  box,  each $120  00 

Cheaper  grades  of  Sextants  and  Octants,  in  metal  or  wood,  kept  in  stock. 

We  keep  supplies  for  sextants  always  on  hand. 

No  113.  Pocket  or  BOX  Sextant.  A  small  instrument,  encased  in  a 
brass  box;  has  a  telescope  sight  and  colored  glasses  attached,  so  that  it 
may  be  used  for  both  field  and  nautical  observations s42  50 


1 13  a.     Angle   Mirrors   or   Prisms.   Small  pocket  instruments  for  laying  off 

right  angles.     Useful  in  field  work.     Price  varies  from $5  00  to  §10  00 

ARTIFICIAL   HORIZONS. 

No.  114.  Mercurial  Horizon,  iron  trough,  iron  bottle  with  screw  stopper  and 

funnel  cap,  glazed  metal  roof.  All  in  polished  mahogany  box $27  50 

No.  115.  Reflecting  Horizon,  black  glass  plane  mounted  in  brass,  with  three 

leveling  screws  and  spirit  level,  in  polished  mahogany  case,  each 10  00 

HELIOTROPES. 

No.  116.      Gauss'  Heliotrope $150  00 

No.  117.     The  telescope  body  is  an  iron  tube,  in  the  middle  is  a  wood  screw 

with  joint  for  attaching  the  instrument  to  a  tree  or  post.     Price  in  box,     30  00 
No.  1 18.     Heliotrope  as  made  by  us  for  the  United  States  Coast  and  Geodetic 

Survey,  with  wooden  base,  mirrors  4x4 35  00 

No.  119.     Same  as  before,  but  with  mirror  6x6 • 41  50 

No.  120.     Same,  with  mirror  8x8 . .      48  50 

Price.,  for  larger  sizes  on  application. 
No.  121.     Pocket  Heliotrope,  Steiiiheil's,  a  beautiful  instrument  that  requires 

110  adjustment.     In  case -•>  00 

Extras  to  Heliotrope,   Nos.  118  to  120  inclusive. 

121  a.  Tangent  screws  for  vertical  and  horizontal  movement 7  50 

121  b.Outlifting  arrangement  for  tangent  screws 5  00 

194 


No.  121  c. 
ANEROID  AND  ALTITUDE   BAROMETERS. 


Prices  from  $12  to  $6O,  according-  to  size  and  altitude  scale. 
Aneroid  barometers  are  made  expressly  for  us  by  the  best  makers,  in  German 
silver  or  nickel  plated  cases,  truly  compensated  for  temperature,  with  or  without 
thermometers,  ranging  from  5,000  feet  to  20,000  feet,  size,    If,  2|  and  5  inches. 
Guaranteed  correct,  every  one  being  subjected  to  a  severe  test  before  being  sold. 

i2id.  MERCURIAL  STANDARD   MOUNTAIN  AND  SEA 

BAROMETERS. 
Prices  from  $2O.OO  to  $1OO.OO. 

Supplies  for  these  barometers,  as  tubes,  mercury  packings,  etc.,  we  have  con- 
stantly on  hand. 

No.  121  e. 

Goldschmid  Aneroid,  as  made  by  Hottinger  of  Zurich,  complete  in 
leathern  case,  with  thermometer  and  tables  showing  rating,  graduated 
to  read  to  millimeters  (see  description  of  this  instrument  in  Part  III 
of  this  Manual).  Prices  range  from $~>0  00  up 

195 


No.  121  f. 

ACHROMATIC   FIELD  AND   MARINE  GLASSES 
AND  TELESCOPES. 


Prices  vary  according  to  size  and  quality,  and  range  from  $8.5O  to  $25. OO 

No.  121  g.  BINOCULAR  TELESCOPES. 

These  telescopes  are  similar  in  construction  to  the  ordinary  field  glasses,  but 
possess  a  much  higher  magnifying  power;  for  this  reason  they  ai*e  very  extensively 
used,  especially  where  a  large  field  in  connection  with  a  hi^h  power  is  desirable. 

Prices  from  $25. OO  to  $52. OO. 


ODOMETERS. 

No.  122.  Odometer  for  measuring  distances  by  wagon.  It  is  enclosed  in  a 
brass  box,  4J  inches  diameter,  furnished  with  leathern  case  and  double 
straps  to  fasten  to  the  center  of  the  wheel.  It  is  the  most  correct  instil- 
ment for  practical  use.  Price ,,„....,.. $17  00 

196 


PEDOMETERS. 

Nos.  123  to  125. 

Pedometers  are   pocket  instruments  for  measuring  the  distance  traversed  in 
walking,  the  number  of  miles  being  registered  by  a  mechanism  inclosed  i:i  a  nickel- 
plated  watch  casing,  and  operated  by  the  motion  of  the  body. 
No.  123.     Pedometer,  watch  pattern,  nickel  case,  IJ-iiich,  registering  12  inih-s 

by  \  mile.     Price £-4  50 

No.  124.     The  same;  registering  50  miles  by  80  yards 5  25 

No.  12).     The  same;  registering  single  steps  up  to  100,000 $G  50 

Nos.  126  and  127. 

Level  constructed  for  the  use  of  Millwrights,  Machinists 
and  Carpenters.  The  iron  frame  is  23  inches  long;  has  two  adjustable  levels 
6  and  3  inches  long. 

No.  126.     With  common  levels §15  00 

No.  127.     Same,  with  ground  levels 20  00 

12/a.  Anemometers    or   Wind   Gauges,   improved  pattern.      Prices   from  $17  00 
to  $35  00. 

No:  128.     SACCHARIMETER. 

An  instrument  for  estimating  the  percentage  of  sugar  in  fluids. 

With  tube  for  liquids,  8  inches  long,  made  to  slide  in  a  brass  tube,  that  carries 
a  polarizer  and  double  quartz  plate  at  one  end,  and  at  the  other  an  analyzer  with 
divided  circle.  The  circle  is  graduated  to  thirty  minute's  and  may  be  estimated  to 
six  miimtes  with  accuracy. 

Observation  is  made  by  adjusting  the  so-called  transition  color  on  both  halves 
of  the  quartz  plate,  the  tube  being  directed  by  hand  towards  a  white  surface.  Suit- 
able for  fluids  containing  a  small  percentage  of  sugar.  Complete  with  directions. 

Price $40  00 

No.  12:).  POCKET  SPECTROSCOPE  (Browning's  pattern),  for  observ- 
ing the  effect  of  absorption  in  larger  objects,  with  adjustable  slit  and  Amici  prism 
of  high  dispersion. 

1293.  Without  comparison  prism $20  00 

I29b.  With  "  "      30  00 

129 c.   MICROSCOPES. 

We  keep  in  stock  microscopes  for  professional  purposes. 
Special  designs  made  to  order. 

i29d.  EQUATORIAL   MOUNTINGS. 

Portable  equatorial  mountings  are  made  to  order  for  the  amateur,  for  schools 
and  colleges,  from  $35  00  to  f  150  00. 

i29e.  POCKET   MAGNIFIERS. 

Heading  glasses  especially  adapted  for  observing  the  vernier  and  needle  of  tran- 
sits, single  or  double  glasses,  in  hard  rubber  or  celluloid  cases,  from  50  cents  to  $2  00. 

197 


No. 

DRAWING  INSTRUMENTS  AND  SUPPLIES. 

Different  grades  and  styles  are  constantly  kept  in  stock,  in  sets  as  well  as  in 
single  pieces.  We  furnish  our  patrons  with  any  desired  make  and  will  send  prices 
upon  application. 

Single  instruments  always  011  hand,  consisting  of  dividers,  plain  and  with  the 
accessories  of  pin  point,  extension  leg,  pencil  point,  pen,  etc.;  proportional  dividers; 
bow  pens  and  pencils;  steppers;  beam  compasses;  drawing  pens;  dotting  pens;  road 
and  railway  pens;  curve  pens;  folding  and  rolling  parallel  rulers,  etc.,  etc. 

Drawing  paper  of  any  desired  quality  is  supplied,  as  well  as  cross-section  paper, 
profile  paper,  tracing  cloth,  tracing  paper,  drawing  pencils,  rubber,  colors  and  color 
dishes,  brushes,  thumb  tacks,  note  books  for  field  and  office.  We  can  always  fur- 
nish our  customers  with  office  supplies  of  any  kind  at  the  shortest  notice. 

Drawing  boards  or  trestles,  or  any  combination  made  to  order. 

PROTRACTORS. 

No.  129  g. 

Three-armed  protractor  or  station  pointer,  as  used  in  plotting  hydrography 
by  the  U.  S.  Coast  and  Geodetic  Survey,  graduated  to  read  to  minutes, 
with  verniers  and  reading  glass,  extension  arms  and  center  plugs,  com- 
plete in  fine  case,  securely  packed , $80  00 

Cheaper  grades  upon  application. 
These  articles  will  be  made  to  order  to  suit  any  particular  line  of  work. 

No.   lagh. 
Circular  and  semi-circular  German  silver  protractors,  graduated  as  required, 

with  or  without  verniers,  from 60c.  to  $20  00 

No.   129  i. 
Paper,  horn,  ivory  and  boxwood  protractors,  from 15c.  to  $15  00 


No.   129]. 
GERMAN    SILVER    PROTRACTOR. 

5yt.inch  diameter,  arm  11  inches  long  from  center,  divided  to  30  minutes,  figures  as 

desired 

198 


SCALES. 


Jo.  130.     Flat  Box^ 

ood  Scale,  C-iiich,  cliv.  10x50  parts  to  the  hit 

h,  each  .  .  .  .  $o  50 

131. 

• 

6     ' 

1 

20X40       " 

' 

50 

132. 

' 

G     ' 

• 

30X60       " 

' 

50 

133. 

* 

G     ' 

' 

s^xico    " 

1 

....       75 

134. 

' 

12     ' 

' 

10X50       "         " 

. 

....       75 

13.>. 

' 

12     ' 

1 

20x40       " 

' 

....       75 

136. 

' 

12     • 

1 

30X60       " 

' 

75 

137. 

• 

12     ' 

« 

80X100     " 

' 

I    20 

138.    Flat  Celluloid-edged  Scale,  G-iiich,  div.  10x50  parts  to  the  inch,  each       75 

139. 

"       0     " 

20X40 

'         " 

'         ' 

75 

140. 

"       G     " 

30X00 

'         " 

'         .' 

75 

141. 

0     " 

80X100 

'         " 

'          * 

I    00 

142. 

«      12     " 

10X50 

'         " 

'          < 

i  25 

143. 

«         ]0        « 

20X40 

f         a 

'          < 

i  25 

144. 

«         ]0        " 

30XGO 

4                   tl 

«         « 

i  25 

14.5. 

«      12     « 

80X100 

<          « 

'         « 

i  75 

Foot  divided  decimally. 

No.  146.  Flat  Celluloid-edged  Scale,  12-inch,  div.  100x500 parts  to  the  foot,  en., 
"    147.      "  "  "      12     "        "    200x400      " 

"    148.      "  "  "      12     "        "    300X600      " 

<(    j49       «  «  «      12     «        «    800X1000    " 


Triangular  Boxwood  Scales,  Engineer's,  div.  10,  20,  30,  40,  50,  60  parts  to  the  ii  ch. 

No.  150.       6-inch,  each 

"    151.      12     " 


25 

25 
25 
75 


oo 
75 

Triangular  Celluloid-edged  Scales,  Engineer's. 

No.  152.       6  inches  long,  divided  like  Nos.  150  aad  151,  each $i   50 

"    153.     12       "  "  "  "        "     150  and  151,      "     250 

Divided  for  Architects  at  same  prices. 

particular  scale,  for  any  purpose  whatever,  upon  any  material,  engraved 
to  order. 


TRANSPARENT  AMBER  TRIANGLES. 

5         6 


30x60°—  Inches.  4  5  7 

No.  154.  Each,  $0.25  .35  .40  .45  .55 

45°.—  Inches,  4  5  6  7 

No.  155.  Each,  $0.35  .45  .55  .65  .75 


9 
.65 

9 
.95 


10 
.75 
10 
i.io 


1 1 

.85 


12 
I.OO 

12 
1.65 


14 
1.65 

1.4 

2  20 


16 

2  50 

16 
3-iS 


Amber  Lettering  Angles,  per  set  (3) $1.50 


MAHOGANY  STRAIGHT-EDGES. 

TRANSPARENT   AMBER    KDGES. 

Inches,  18  24  30  36  42  48 

No.  156.     Each,        $0.75         i  oo         1.25         1.50         1.80         2  20 

Triangles  and  Curves  of  rubber  and  wood  kept  in  stock  and  supplied. 


SLIDE   RULES. 

No.  157.  Dennert  &  Pape's  logarithmic  slide  scale,  (Mannheim  Rule)  10  inches 
long,  celluloid  covered,  graduated  as  described  in  the  discussion  of  the  use  of 
this  scale  in  Part  III  of  this  Manual $4-5O 


Jyy 


McCULLOUGH  TAPE   LEVEL, 
No.  158. 


(Pat.  July  26,  1892 .) 

Insures  accuracy  in  measurements  with  steel  tapes.  Above  cut  full  size. 
Weight  one  ounce.  It  is  used  by  clamping  to  the  tape,  about  one  foot  from  the 
handle,  by  means  of  the  two  springs  shown,  and  can  be  attached  and  detached 
instantly. 

Price,  Sl.OO 


No.  159.  THERMOMETERS. 

A  full  supply  of  thermometers,  plain,  maximum  and  minimum,  and  hygrome- 
ters kept  in  stock. 


NAUTICAL  INSTRUMENTS. 

This  catalogue  does  not  contain  our  supply  of  nautical  instruments,  of  which 
we  keep  in  stock  a  number  of  the  usual  articles  required  by  the  navigator,  partic- 
ularly in  the  line  of  ship's  compasses  and  logs.  In  the  near  future  a  price  list  of 
these  goods  will  be  published  by  the  Company,  but  for  the  present  a  mere  reference 
to  this  branch  of  our  work  shall  only  be  made  here. 

See  our  Special  Catalogue  for  Nautical  Goods. 


INDEX. 

No.  or  Page. 

Address  an  instrument  to  the  Company,  how  to 59 

Adjusting  Room,  the 4 

Adjustments,  charges  for 58 

' '            collimators   for 4 

"             of  the  dumpy  level 7° 

*              of  the  plane-table  alidade 77 

"            of  the  transit 60 

"             of  the  Y-level 66 

Agate  fittings  for  Y-level 44,  160 

Agate  setting  for  needle 23 

Air  pump  for  testing  aneroids 6 

Airy  eye-piece,  the 33 

Alidade,  adjustment  of  the 77 

"         the  plane-table 47 

"         of  aluminium 49 

Alt- Azimuth  instrument 178,  179 

Altimeter,  Abneys , 187 

Aluminium  alloys 48 

adaptability  of 4,  47,  52,  101 

alidade 49 

instruments,  stability  of 48 

levels 49 

solar  attachments 49 

transits 49 

Anemometers 197 

Aneroid,  the  Goldschmid 104,  195 

Angle  mirrors 1 94 

Artificial  horizons 194 

Axes  of  transit  telescopes 25 

Balsam  used  in  lenses 37 

Barograph  (self- registering  aneroid  ) 106 

Barometers,  Aneroid 195 

Goldschmid  Aneroid 104 

Bell  metal,  use  of 42,  49 

Bending  of  plates  and  centers 54 

Bessel's  spheroid,  elements  of 107 

Careless  handling  of  instruments 52 

Care  of  instruments 52 

Case,  the  instrument 38,  44,  102 

Centering  apparatus,  the 4 

"          the  field  of  view 65 

Center  pin  for  needle,  adjusting 23,  55 

Centers,  bending  of 54 

"        length  of 19 

"        of  dumpy  level 45 

"        of  Y-level 40 

"        or  vertical  axis,  the ._ 18 

"        single,  cyclotomic 121-126,  153-156 


Chain  Pins 189 

Chains,  Surve)ors' 189 

Chromatic  aberration,  test  for   73 

Circle,  horizontal 20 

"        vertical 25 

"  "       adjustment  of 65 

Clamp   screws 22,  102 

Clarke's  Spheroid,  elements  of 107 

Clinometers 188 

Cloth-finish,  dumpy  level 45 

Y-level 43 

' '  telescope  standards 25 

Clothing,  influence  on  needle 55 

Collars  of  the  Y-level 42 

"        the  inequality  of. 42,  69 

Collar  test,  the 69 

Collimation,  line  of 62 

Collimators,  the  mural 4 

Compass,  graduation  of  the 23 

"        needle 22,  101 

"        pocket 187 

' '        prismatic 1 86 

"        repairs  to 58 

* '        Surveyors' 186 

Conical  bearings  of  telescope  axis 25 

Construction  of  instruments 101 

Correspondence  regarding  repairs 57 

Cost  of  repairs 58 

Cross-hairs,  adjustment  of. 62,  68,  71 

"  frame  for 34 

' '  glass  diaphragm  for 35 

' '  how  to  replace 56 

Crown  glass  in  lenses 31 

Cyclotomic   transit 121-126,  153-156 

Definition  of  telescopes 42,  72 

Dividing  engine,  large  circular 4 

"       linear 6 

Directors  of  the  A.  Lietz  Company VI 

Drawing  instruments 198 

Dumpy  level,  the 44 

"           "      adjustment  of 70 

"           "      centers  of. 45 

"           "      cloth -finished 45 

\  "           "      of  aluminium 49 

"           "      price  of 161,  162 

Dust  caps. 18 

Eccentricity  19 

"  graphical  determination  of .103 

Electric  currents,  influence  of,  on  needle VIII 


Emery,  danger  of  using 54 

Equatorial , 173 

Equatorial  mountings , 197 

Establishment,  description  of  the  A.  Lietz 2 

Eye-piece,  the 32 

"          care  of ; 56 

the  Airy 33 

the   erect 33 

the  Huyghens 33 

the  inverting ; 33 

the  Kellner 32 

the   negative 33 

the  positive 33 

the  Ramsden 32 

the  Steinheil 32 

the   terrestrial 33 

Field  glasses 196 

Finish  of  instruments,  the 38,  43,  102 

Flatness  of  field,  test  for 73 

Flint  glass  in  lenses 31 

Focal  length,  apparatus  for  determining  the 75 

Focal  length  of  objectives 32 

Foundry  the 2 

Fretting  of  working  parts 53 

Glass  diaphragms  for  cross-lines 35 

Goldschmid  Aneroid,  the 104 

Gradienter,  observing  horizontal  distances  by  the 26 

Gradienter,  the 25 

Graduation,  accuracy  of  lines 99 

of  compass 23 

on  solid  silver 20 

plate,  the 19 

room,  the 4 

"          tester,  the 4 

Heliotropes 194 

How  to  tell  a  good  surveying  instrument 99 

Hnyghens  eye-piece,  the 33 

Illumination  of  cross-hairs 34 

Importations ,   6 

Incorporation  of  the  A.  Lietz   Company VII 

"  Irrigation  Age,"  extract  from 8 

Jena  Glass  Works 27 

Kellner  eye-piece,  the 32 

Lamps,  illuminating 189 

Latitude  coefficients,  table  of 1 18 

"  length  of  one  minute  of 109 

Lenses,  balsaming  of 37 

"      centering  of 32,  37,  56,  68 


Lenses   cleaning  of 56 

"       imported 6 

"       staining  of 56 

"       transit  telescope . 27 

Level,  Dumpy  (see  U) 44 

"      German  Pocket 45,1 63-167 

"      Hand    I87 

instrument 40 

' '      McCullough  tape 200 

"      Millwright's,  Carpenter's  and  Machinist's 197 

' '      Reflecting  ( Abneys) 187 

"      Reversion slip  134  A 

"      Rod 187 

' '      screws 17 

' '      sensitiveness  of  bubble 26,  40,  58 

"      tester 6,  27 

Y-Level,  the 40 

"         adjustments 66 

' '         agate  fittings 44 

"         aluminium 49 

"         center  of 40 

"         cloth-finish  of 43 

"         collars  of 42 

"         curvature  of  tube 40 

"         magnifying  power  of 41 

"         packing  in  case 44 

"         precision 44 

"         price  of 159,  160 

"         repairs  to 58 

Lifting  arrangement  of  needle 23 

Longitude,  how  to  find  the  length  of  one  minute  of 107 

Lubrication  of  certain  parts 54 

Magnetic  attraction  in  clothing 55 

Magnetic   needle 22,  101 

Magnetic  variation,  to  set  off  the 24,  Slip  VIII  A 

Magnifiers,  Pocket 197 

Magnifying  power  of  telescopes 36,  41 

"  "       to  find  the 74 

Marking  tools 189 

Mechanical  devices  made 6 

Meridian  instruments 175 

Metal  tester,  the 6 

Microscopes 197 

Mining  transit,  with  inclined  standards 157 

Models  made,    mechanical 6 

Nautical  Department,  the 6 

"       Mile,  length  of 109 

Needle,  the  magnetic 22,  101 

*'       center-cap  of 23 


Needle  center-pin  of. 23 

"  lifting  arrangement  of 23 

to  restore  magnetism  of 55 

to  preserve  sensitveness  of 54 

Nonius,  the 20 

Object  glass,  the 31 

Objectives,  focal  length  of , 32 

Odometers .' 196 

Optical  axis,  coincidence  of 32,  37,  56,  68 

Orthoscopic  eye-piece 32 

Packing  transit  in  case 38 

' '         level  in  case 44 

Parallax,  adjustment  of 60,  69 

Parallelism  of  collars  in  Y-level 67 

"  "     telescope  in  Y-level 66 

Pedometers 197 

Plane-table,  the 47 

"  adjustment  of  alidade 77 

price  of 169,  170 

Planimeters 184,  185 

Plates,  bending  of 54 

"     horizontal 19 

"     levels  for 60 

Plumb-bobs 189 

Plumbing  arrangemen t 18 

Poles,  Sight 171,  172 

Prices  of  Dumpy  level 161,  162 

"     German  level 165,  166, 167 

"     Y-level 159,  160 

"     Plane-table 169,  170 

"     Theodolite 139,  140 

"     Transit,  complete 135-138 

"         "          compound  mining  and  solar 147-152 

"         "          cyclotomic 153-156 

mining 143 

mountain  and  mining 141,  142 

plain 131,  132 

with  telescope  level 133,  134 

compasses 145,  146 

Protection  from   rain 53 

"  "     sun 53 

Protractors 198 

Ramsden  eye-piece,  the 32 

Reconnoissance  transit,  cyclotomic 154,  156 

Reflecting  circles 182,  183 

Refraction  correction  table 119,  120 

Refraction  table,  mean 114 

Remarks  on  instruments 46,  99 

Repairs 57 

"      cost  of ...     58 

"       what  to  send 58 


Reversion  level slip  134   A 

Right-angles,  arrangement  for  laying  off 38 

Rods,  level 171,  172 

"       sight . . . 171,   172 

"       Stadia  (flexible) 172 

Rules,  Slide 199 

Saccharimeter 197 

Saegmiiller  Solar  Attachment 38,  49,  no 

Scales 199 

Screws,  overstraining 53 

Seismograph 1 68 

Sextants 194 

Shake  in  the  slide 34 

tripod 54 

Shifting  center 18,  102 

Shipping  an  instrument 1 1,  59 

Shoes,  tripod 39 

Silver,  graduation  on  solid 20 

Simplified  transit  compasses 145,  146 

Size  of  transits :v  38 

"  levels 1 58-167 

Slide,  the 34,  53 

"      protector,  the 34'  43 

"     rules 199 

*'  scale,  the  logarithmic 91 

Solar  attachment 38 

Solar  attachment  of  aluminium 49 

Solar  attachment,  Saegmiiller 38,  49,  no 

Spectroscopes 197 

Spherical  aberration,  test  for 72 

Spheroid,  elements  of  the  terrestrial 107 

Spider  web,  the 34 

Spirit  levels  (vials) 6,  26 

"  "  importance  of  sensitive 26 

Stability  of  instruments 17.  IO1 

"  "  aluminium  instruments 48,  101 

Stadia  hairs,  fixed. .  . . 35,  44,  45 

"  "  adjustable 35 

Stadia  reduction  tables 86 

"  surveying,  treatise  on 80 

Standards,  the 24,  102 

"  unequal  expansion  in 25 

Star-shaped  casting  for  leveling  screws IV,  IO2 

Station  pointer 19$ 

Steel  center  in  Y-level 4°,  49 

Steinheil  eye-piece,  the ; 32 

Straight  edges *99 

Sunshade,  the 34>  43 

Surveying  instrument,  how  to  tell  a  good 99 


Vll 

Tables,  mean  refraction 114 

"      of  latitude  coefficients 118 

"      refraction  correction 1 19,  I2O 

"      stadia  reduction 87 

Tangent  screws 22,  102 

Tape  lines  (steel  and  metallic) 190-192 

"          ribbons 193 

Telescope,  accurate  balance  of 36 

bearings,  adjustment  of. 6 1 

"          cleaning  of 55 

' '          definition  of. . .    72 

finding  the  magnifying  power  of  a 74 

general  remarks  on 36,  99 

level 41 

"  "     adjustment  of 64,  68 

"          magnifying  power  of. 36 

reversibility  of  transit 36 

"          test  of 72 

transit 27 

"  "      adjustment  of , 6 1 

Testimonials  (on  first  leaves  of  Manual). 

Theodolite,  description  of 14 

' '  highest  grade ; .  . .     47 

with  micrometers 18 1 

price  of 139,  140 

size  of 140 

Three-leveling-screw  arrangement 18 

Thermometers 200 

Transit,  adjustments  of  the 60-66 

' '       aluminium 49 

"       centers  of. 18 

"       cyclotomic 121-126,  153-156 

"       description  of 14 

"       mining,  with  inclined  standards 157 

"       packing  in  case 38 

"       price  of 134-158 

"       reconnoissance  (cyclotomic) 154,  156 

"       repairs  to 58 

"       simplified  (compasses) 145-148 

"      single  center,  cyclotomic 121-126,  153-156 

"      sizes  of 134-158 

Triangles 199 

Tripod  connection 15,  102 

"      coupling,  the  new  Lietz 15,  16 

"      shake  in 54 

"      split  leg 39 

Variation,  setting  off  the  magnetic 24 

"          plate 23 

Vernier,  the 20 

"         position  of 21,  IOI 


Vernier,  protected  by  glass 21 

"         shades 21 

"        theory  of  the 21 

Vertical  arc . 25 

"        "  adjustment  of  the 65 

Werner,  Peter 21 

Workshop,  description  of  the .  2 

Y-level  (see  level) .  .  40 

Zero  of  vertical  arc 65 


LIST  OF  ILLUSTRATIONS. 


PART  I. 

Page 

Plate  I.     Interior  View  of  Workshop IX 

"     2.      Interior  of  Graduating  and  Adjusting  Room 3 

"     3.     Circular  Dividing  Engine 5 

"     4.     Centering  Apparatus  for  Testing  Graduations 7 

' '     4.     Linear  Dividing  Engine 7 

"     5.     Level  Tester 9 

"     5-     Apparatus  for  Testing  Magnetic  Influence . 9 

"     6.     Mural  Collimator  Apparatus II 

PART  II. 

The  Lietz  Tripod  Coupling 16 

Apparatus  lor  Measuring  the  Focal  Length 76 

PART  III. 

Figure  i.     Diagram  of  Optical  Features  in  Telescope 81 

"       2.     Diagram  showing  Stadia  Reductions 83 

Figures  1-5.     Logarithmic  Scales 98 

"        A,  B  and  C.     Magnified  Graduation  Lines 99 

Graphical  Determination  of  Eccentricity 103 

"          I,  2  and  3.     Goldschmid  Aneroid  Barometer 105 

Saegmiiller  Solar  Attachment 1 12 

Spherical  Triangle 113 

Figure  I.      Section  of  Cyclotomic  Transit 122 

Figures  2  and  3.     Views  of  Plate  of  Cyclotomic  Transit ....    123 

PART  IV. 

Plain  Transit 131 

Transit,  with  Telescope  Level 133 

Complete  Engineer's  Transit 135 

Complete  Engineer's  Transit 137 

Complete  Transit-Theodolite , 139 

Complete  Mountain  and  Mining  Transit 141 

Simplified  Transits  (Compasses) 145 

Compound  Mining  and  Solar  Instrument 147 

Compound  Mining  and  Solar  Transit 149 

Compound  Mining  and  Solar  Transit 151 

Cyclotomic  Transit 1 53 

Mining  Transit,  with  Inclined  Standards 1 57 

Y  -Level 1 59 


Dumpy  Levels 16 1 

Section  of  German  Level  Telescope 164 

German  Levels 165 

Complete  Pocket  Surveying  Inslrument 167 

Seismograph 168 

Plane-table 169 

Leveling  Rods  and  Range  Poles 171 

Equatorial 173 

Meridian  Instrument 175 

Alt-Azimuth  Instruments 177-176 

Theodolite  with  Micronometers 1 8 1 

Reflecting  Circles 182,  183 

Amsler's  Planimeter 1 84 

Surveyor's  Compasses    ,    1 86,  187 

Lock's  Hand  Level 187 

Atwood's  Clinometer 188 

Steel  Tape  Lines 190-193 

Altitude  Barometer 195 

Field  Glasses , 196 

Protractor 1 98 

McCullough  Tape  Level 200 


1 


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1  1  778          BERKELEY,  CA  94720 


